ey everyone, and welcome back to Online Tech! This week, I gave the Poison Sliver deck a spin in online Time Spiral Block Constructed tournaments. I got a good feel for the deck for the deck and I'll tell you what I think about it shortly. But first, let's take a look at the metagame breakdown of the Premier Event Top 8s of the last two weeks.
Tarmogoyf beatdown decks account for 34% of the metagame, and the blue variant appears to perform the best of the bunch. Other beatdown-oriented decks make up 18% of the metagame. All control decks lumped together add up to 45%, so it seems that the current metagame is split approximately equal between aggro and control decks, with perhaps a slight nod towards aggro. Combo decks are nearly non-existent.
The metagame is relatively stable, which is evident from the similarities in percentages between the two weeks. Perhaps an interesting trend, though, is the recent rise of Red Deck Wins again. It had trouble beating fat Tarmogoyfs and life-swinging Tendrils of Corruptions, but recent innovations such as the addition of Riddle of Lightning and Akroma, Angel of Fury give it a fighting chance again. These cards make the deck a bit slower – more towards a Big Red concept – but they give the deck a bit more oomph and late game power. Akroma, Angel of Fury is immune to Temporal Isolation and blue bounce. Moreover, it hits right through Mystic Enforcer and Riftwing Cloudskates. Riddle of Lightning can hit Greater Gargadon for 10 damage or Akroma for 8 damage. You have to get a bit lucky, but it can steal games from out of nowhere.
Mono Blue Pickles has slowly but steadily risen to the top ranks. I would still prefer U/B/w/r Teachings Control as my deck of choice – Damnation is too strong to pass up, in my opinion – but other top players have voiced their support for the Brine Elemental plan. Kenji Tsumura's version from the Grand Prix Montreal Top 8 is the most prevalent build online, and he himself has won a 100 man Time Spiral Block Constructed IPA Qualifier with Mono Blue Pickles. This is how a typical build looks:
Kenji Tsumura's Mono Blue Pickles
It is certainly one of the most powerful and consistent decks around. It plays 8 bounce spells, so it can play a good tempo game. It plays 7 counterspells, so it can take a control stance as well. It has 4 Vesuvan Shapeshifter and 4 Brine Elemental, so it can lock you down easily. And when you point a removal spell to a morph, fearing that it might be Brine Elemental, suddenly a Willbender can surprise you by turning that removal spell on your own creatures. From my experience – mostly based on a lot of games against Kenji in Montreal – the match-up with U/B/w/r Teachings Control is very close and heavily dependent on playing skill. I don't believe people who claim that Mono Blue Pickles smashes U/B/w/r Teachings Control, but I also admit that Pickles is one of the match-ups I want to face the least if I am playing Teachings.
So how good is that Poison Slivers deck?
I took up this stock version and played a couple games in the Tournament Practice room in order to learn how it worked.
wrapter and mikeman29's Poison Slivers
I then played in two Premier Events. I kept track of the games I played, and I will go over them round-by-round to offer some highlights and to give you an idea of how this deck plays out. On to the first tournament I played in; #1001827.
Round 1: himanchu, U/B Teachings Control
My inaugural game offered a blazing fast draw. I started with turn 1 Screeching Sliver
, then turn 2 Gemhide Sliver
plus Virulent Sliver
. On turn 3 I can already attack for 3 poison counters, and I add Screeching Sliver
plus Two-Headed Sliver
to the board as well. He's poisoned on turn 5.
In the second game, I keep a questionable hand with Virulent Sliver, Two-Headed Sliver, 2 Bust//Boom, and 3 lands. In hindsight, I think I should have taken a mulligan, since I don't have enough Slivers to make for a fast poison kill, and I am missing the most important Slivers against his deck: Frenetic Sliver and Dormant Sliver to dodge the impact of Damnation. Furthermore, I don't have the pressure or the Gemhide Sliver needed to capitalize on Bust//Boom.
But I chose to keep and lost. He clears the board with Damnation just before dying to poison. My turn 3 Boom (targeting my own Terramorphic Expanse, which I sacrifice in response so that I won't lose a land) and my turn 6 Bust are both met with a Cancel. Now I am out of gas, and he starts Triskelavus plus Academy Ruins recursion to take the game.
In the third game, I play a Screeching Sliver, Frenetic Sliver, and Dormant Sliver on the first couple of turns. I am drawing multiple extra cards per turn due to Dormant, and his removal doesn't work well due to Frenetic. I shortly find a Telekinetic Sliver and start locking down his lands in his upkeep.
Two turns later I have found two Virulent Slivers. I use Frenetic's ability to get rid of Dormant, allowing my Slivers to attack again, and poison him out of the game.
Round 2: LestatdL, Mono Blue Pickles
In game 1, my mulligan to five gives the dream hand with double Virulent Sliver and a Two-Headed Sliver. C'mon poison! He plays turn 1 Island, Ancestral Visions and I make a Virulent Sliver. Unfortunately, he has the foil on turn 2.
How is my hand supposed to beat that? I try to out-smart him by playing the second Virulent Sliver instead of Two-Headed Sliver on turn 2. I do not want him to know that I have Two-Headed, since now he might tap out to play a morph on turn 3, thinking that it can block my 1/1s, which will allow me to play Two-Headed and sneak in for 4 poison counters. My plan didn't work out though; he just suspends Riftwing Cloudskate and keeps the Desert untapped. Shortly after, he bounces my guys, counters some stuff, and while I am stuck with 3 blue Slivers in hand with no blue mana in play, he finds the Brine Elemental plus Vesuvan Shapeshifter lock.
In game 2, Gemhide Sliver accelerates me into a turn 3 Telekinetic Sliver, which turns my game plan into quickly Opposition-locking him down. Unfortunately, he has Snapback to break free, and then casts Serrated Arrows to take care of the Telekinetic for good. I learned the hard way that Arrows is very good against my deck, especially in combination with Riftwing Cloudskates that allow him to re-use it. The best way to beat Arrows is with Dormant Sliver and Frenetic Sliver to draw cards and protect my Slivers. So I use Homing Sliver to cycle for those, but it's too slow. Multiple Riftwing Cloudskates apply pressure, and I can't recuperate in time.
Round 3: getwet, G/W Tarmogoyf Aggro
In game 1, I cast some cheap Slivers and then Dormant Sliver, with the plan of drawing into Telekinetic Sliver (or Homing Sliver to get it) to tap all of his creatures. I make some Slivers and draw cards; he taps out to make some creatures. I then draw into Summoner's Pact and Virulent Sliver, do the math, and notice that I can simply kill him. No Telekinetic necessary! I sacrifice Dormant to Firewake, make two Virulent Slivers and swing with all. Five creatures go unblocked and give 10 poison counters.
In game 2, he has a very fast start with many creatures. I draw Homing Sliver on turn 4 and quickly search for Telekinetic, but it is already too late. I cannot get Telekinetic online in time. And even if I had, after sideboarding he has Sunlance as an out, which turns the match-up upside down.
In game 3, I mulligan down to 5 in search of a good mix of lands and spells. I cast turn 2 Gemhide Sliver and he Sunlances it. This is the game state in my third turn's main phase.
My game plan with this hand will most likely be to draw lots of Slivers with Dormant, and slowly take control. I have a couple options here. I can play Homing, but that seems bad because it will just be a random 2/2 that won't affect the board. I can also cycle it and then the main choices are Gemhide Sliver (which would allow me to cast my Dormant if I don't draw a fourth land), Telekinetic Sliver (which I need at some point to contain his creatures), or Frenetic Sliver (protect my Dormant from Sunlance). I think it's a close call between Gemhide and Telekinetic. Casting Dormant as soon as possible is important, and I don't have a second blue for Telekinetic yet, so I go for Gemhide Sliver. Note that I cycle in my own turn, because I am afraid of an opposing Vesuva or Pendelhaven, which could destroy mine with the legend rule before I get to tap it for mana. He then starts making Tarmogoyfs and Serra Avengers. I draw cards with Dormant, but I take one turn too long to find a Telekinetic Sliver, and his flyers do me in.
Round 4: DyingStarPilot, UB Teachings Control
In game 1, in the early turns my creatures trade with his counters, but I manage to keep 2 Virulent Slivers in play. I already dealt eight poison counters when he searches Tendrils of Corruption with Mystical Teachings at the end of my turn, and strangely enough he passes the turn without playing the Tendrils.
Note that I already had Pendelhaven in play (which was tapped last turn), and he passed with one Swamp in play. Perhaps he made a mistake and overlooked Pendelhaven. In that case, I should attack: he points Tendrils at one Virulent, I pump it to make it survive, and deal the final poison counters. He could also have Venser, Shaper Savant to survive, but even then attacking is not all that bad, since I can make my Sliver 2/3. There is also the unlikely possibility of him having Teferi, Mage of Zhalfir and Slaughter Pact. Would you attack?
I did, hoping that he made a mistake. Unfortunately, he ambushes me with Teferi and Pact. Oh well. Unfazed, I make Dormant Sliver, next turn another one, and start drawing tons of cards. Once he starts fighting back with removal, I already have a Frenetic Sliver out, and soon enough I have built up a critical mass of Slivers including another Virulent, flip out both of my Dormants, and alpha strike for the poison kill.
In game 2, he has Shadowmage Infiltrator and draws answers to my Slivers every turn. If I cannot keep a Dormant or Frenetic in play against him and I don't have a super fast start with multiple Virulents, I am not going win this match-up.
In game 3, I come out of the gates fast with Virulent and Two-Headed Sliver. He plays Prismatic Lens on turn 2, while I have Gemstone Mine and Harmonic Sliver. Ding! On his next turn, he plays 2 more Prismatic Lens. I almost fall out of my chair due to the ridiculousness of Harmonic Sliver in this game, but in response to my Frenetic Sliver he plays Slaughter Pact on Harmonic. Boooh! Still, my board is quite good and I keep on attacking for multiple points per turn. He doesn't find an answer to my weenies in time.
Round 5: m3r1d14n, Poison Slivers mirror
Okay, the mirror match is very awkward. The way it usually goes is that someone gets out a Dormant Sliver, so he can never be attacked anymore, and then both players start to draw lots of cards off Dormant. The other player has to play a Dormant of his own as well, otherwise his opponent will eventually assemble a mass of Virulent Slivers and a Two-Headed, then flip out his Dormant to Frenetic, and alpha strike for the kill. Soon enough, both players have Dormants and Screeching Slivers (and usually Firewake Sliver as well so every Sliver can start milling right away), and the milling race begins. No player has removal for Dormant main, so the only route to victory is decking. It is usually best to tap a Sliver to mill, not to tap it for Gemhide Sliver mana to cast more Slivers. Note that Dormant's draw is mandatory, so at some point you should usually stop casting Slivers; otherwise you deck yourself too fast. This is exactly how game 1 went. At some point, the board looked like this (I have 24 cards left in my deck and 7 Slivers on the table; he has 16 cards left and 10 Slivers on the table, and it's my main phase).
Should I play another Sliver? At such a point it comes down to counting. He has 10 Slivers, so if he mills me at the end of my turn and in his own turn, he can bring me down to 4 cards. Since there are 3 Dormants in play, I do not want to play another Sliver, because then I have to draw 3 cards, and then he only has to play one Sliver to deck me. If I play no Sliver, then he has to play 4 extra Slivers to deck me, which may in turn deck him due to Dormant. So I don't play a Sliver and pass.
He mills me for 10, draws a card, plays nothing, and I mill him for 7. I draw a card, and in my main phase he now has 8 cards left, and I have 13 (virtually 3 after he mills). I mill him for 7, then play another Sliver – which by the slightest of margins does not deck me – and mill his last card. He loses in his next draw step due to an empty library.
Note that he actually had a way out. He should have milled me down to 4 cards in his own turn, then he should have sacrificed his Dormant Slivers to Firewake Sliver, and then flip out 4 Slivers with Frenetic that hastily mill my final cards when they come back at the end of his turn. This would not deck him if he sacrifices his Dormants first.
After sideboarding for game 2, the way the match-up plays out is still similar, but Dead // Gone changes things. Look at this game state. The opponent has 7 Slivers, including a Dormant. You have 7 Slivers as well. Your hand is 2 Dead // Gone, Two-Headed Sliver, Homing Sliver, Summoner's Pact, Firewake Sliver, and lands.
It is your main phase, and you can win this turn. What is the play? This turn, we can poison him out if we can get 4 unblocked Slivers. Using Two-Headed Sliver, getting unblocked Slivers is not all that hard. But first we have to get rid of the opposing Dormant Sliver so that we can actually attack. That is where Dead // Gone comes in. First, play Dead on Dormant. If he happens to Delay it, then we have another backup Dead // Gone. He doesn't and just uses Frenetic to flip it out.
I then play a land and tap all of them and my Dormant Sliver for 6 mana total. I play Firewake Sliver. It resolves, so now I have protection for an opposing Dead // Gone (I can sacrifice a useless Screeching Sliver to save an important Sliver). I then play Dead // Gone on his Frenetic Sliver. He flips it out. Now he has 5 creatures left, so with Two-Headed he can only block two. I then play a Two-Headed Sliver of my own (I can't rely on his, because he can just take it out with Frenetic or Firewake at will), and cast Summoner's Pact for Virulent Sliver. I tap a Screeching to play that one too, and then flip out my own Dormant Sliver with Frenetic. Now there is no Dormant preventing Slivers from attacking anymore, so I attack with all of my guys (except one, which I keep back so that I can tap it for mana and then sacrifice to Firewake Sliver as a safety net against Dead // Gone). I got him.
Round 6: polybus, Poison Slivers
In game 1, it is the same picture as the previous match all over again. I have a quick Dormant and make lots of slivers. He does the same, but doesn't make a Dormant of his own for a while. Therefore, I am setting up a turn where I Frenetic out my Dormant, then attack with all my Slivers for the kill, but he Slivercycles for a Dormant just in time, which is a smart play. Eventually the board comes down to this and I start calculating. He has 37 cards left in his deck and 7 Slivers in play. I have 33 and have 10 Slivers in play. It is my main phase. Should I play a Sliver?
Let's assume no one adds a Sliver to the board and then count a couple turns ahead.
My deck size
His deck size
1. My end of turn
||He mills me
2. His draw step
||He draws a card
2. His end of turn
||I mill him
3. My draw step
||I draw a card
3. My end of turn
||He mills me
4. His draw step
||He draws a card
4. His end of turn
||I mill him
5. My draw step
||I draw a card
5. My end of turn
||He mills me
6. His draw step
||He draws a card
6. His end of turn
||I mill him
7. My draw step
||I draw a card
7. My end of turn
||We mill each other
8. His draw step
||He draws a card
So far, if nothing happens, I will win. If he plays Slivers to speed up his mill clock, then he has to draw too many cards with Dormant, which speeds up my mill clock as well. I don't see a possible winning strategy for him. I don't have to play my Firewake, since it won't speed up my mill clock, unless he plays two Slivers of his own.
After spending multiple minutes on my calculations, my opponent polybus gets bored and proclaims that this has to be an abysmal mirror match, which I most certainly cannot deny. He then notices that X-2 records don't have a shot for Top 8, and as he doesn't want to waste any more time with this tourney, he concedes the match. Oh well, I can't blame him, this mirror match is indeed a mess.
Round 7: natomage, U/G/r Shifter
In game 1, I make some early Slivers and resolve Telekinetic Sliver. I start tapping his lands, especially his Mountain out of fear of a potential Stormbind, then his biggest creatures. The only thing I have to watch out for is Brine Elemental. Therefore, I tap his blue mana in his upkeep first. If he floats mana, he can flip Brine but I still have enough creatures untapped to tap down his biggest creatures. If he doesn't float mana, he cannot flip Brine and I can tap at will. He doesn't have Brine in the end, I make two Virulent Slivers, tap all his permanents, take out my Dormants, and attack for the kill. I like how Magic Online then gives the message "natomage was poisoned!!!" with not one, not two, but three exclamation marks.
In game 2, I have to mulligan down to 4 because of one or zero landers. He's stuck at one Island though, so we are battling the mulligan to 4 against the mana screw. Eventually, I am able to cycle Homing Sliver for Dormant and start drawing cards. In the meantime he has found a Forest and starts to get back in the game. However, soon enough I have Telekinetic plus Dormant running and I am ready to move in for the standard poison kill, but he had a nice trick up his sleeve.
He turned his Vesuvan Shapeshifters into Dormant Slivers. This is certainly a trick to keep in mind, just like casting Take Possession on Dormant Sliver. This deck can only beat an opposing Dormant Sliver with Screeching Sliver! I still win the match though, as I had more Slivers than he had permanents and milling works.
Final record: 5-2
So far the deck has performed fine. Then I entered another Premier Event; # 1003309.
Round 1 –rmiller99, Mono Green Aggro
I trade some early Screeching Slivers with cards of his, and then my assault comes to a halt. I play Summoner's Pact for Dormant Sliver once I have 2 green mana (I need to pay the upkeep). Then I draw into Homing Sliver, which fetches Telekinetic Sliver. I tap down his creatures, draw cards with Dormant, and eventually find a second Virulent Sliver and attack for the kill.
In game 2, I start with turn 2 Gemhide Sliver and hold Telekinetic Sliver, Firewake Sliver, and Two-Headed Sliver. I play Firewake Sliver and Two-Headed on turn 3, and then Telekinetic Sliver and other Slivers on turn 4. This is more mana efficient, and the Firewake plus Gemhide combo allows you to dump your hand on the table in short order. Soon enough I have 8 Slivers in play; so first I attack him down to 16 life and use my remaining Slivers to tap his board. Then next turn I attack with a 2/2 Sliver, tap all my other Slivers for mana, then sac them all to Firewake on the unblocked one: a 16/16 for the win.
Round 2 – wrapter, U/B/r Control
In game 1, a lack of red mana slows me down. Once I find a Mountain and start casting my red Slivers, it is already too late. Void and Bogardan Hellkite clear the board, and his 5/5 starts attacking for the win.
Game 2 comes down to a turn where he Slaughter Pacts my Dormant Sliver and then passes the turn.
Do you see it? Bust for the game! I destroy all lands, and then he is unable to pay the upkeep for his Pact.
Game 3 offers a slow hand again, but adding Boom//Bust and Delay to the deck means taking out some creatures, so slow hands are to be expected. I make a lot of Dormant Slivers and tutor for new ones, but he answers each and every one of them. Strangling Soot; Cancel. Pact of Negation all say no. He then clears my remaining board with Bogardan Hellkite, uses a Void to pick off the stragglers, and attacks with his dragon.
Round 3 - subliminal man2, G/R Wild Pair
In game 1, I curve into a turn 4 Dormant Sliver and start drawing cards. In the meantime he is accelerating with Wall of Roots into a quick Wild Pair. I draw into Delay, which counters his Primal Forcemage in order to prevent him from using Wild Pair. I win on the next turn.
In game 2, I make turn 1 and 3 Slivers and then turn 4 Telekinetic, planning to start locking his lands. But he has the cheapest Damnation ever in Rough//Tumble to take them out. I recuperate with Dormant, while he makes Wild Pair. I Summoner's Pact for Harmonic Sliver, which I play on the back of Gemstone Mine. I decide to Delay another Rough//Tumble to keep my Dormant alive, but that allows him to resolve Bogardan Hellkite. Soon enough he makes another Wild Pair, and my back is against the wall.
I play Sliver after Sliver in search for Delay. I need a Delay to stop his Grinning Ignus from triggering his Wild Pair over and over again (which would mean Primal Forcemage into multiple Bogardan Hellkites). I don't find a Delay. I have no other choice. In my main phase I start flipping out slivers to Frenetic, except for Dormant Sliver, Gemhide Sliver, and Firewake Sliver, which I certainly need to keep. I won a couple flips, and they all come back at the end of my turn to give me more cards via Dormant. Unfortunately, I don't draw Delay and still lose on his next turn.
In game 3, I mulligan into 4 land, Firewake Sliver, Frenetic Sliver. I keep and make those on turn 3 and 4. He casts Wall of Roots, Harmonize, and multiple Dead/Gones to destroy my team. The coin flips don't land in my favor. I play Dormant Sliver, but he is already up to eight mana and casts Bogardan Hellkite to kill it. I don't recover.
Round 4 - Dark Circle, Mono Black Discard Fatties
In game 1, I have a great opening hand with all the good Slivers, but he uses Augur of Skulls and Stupor to tear my hand apart. I choose to keep my Dormant Sliver, but Sudden Death kills it. Multiple Damnations kill my remaining weak Slivers, and then I have nothing left. He takes the initiative with Tombstalker and Stronghold Overseer, and I don't draw Telekinetic Sliver.
In game 2, I come out well with turn 3 Frenetic Sliver, turn 4 Dormant Sliver, and turn 5 Telekinetic Sliver. I commence to lock down his lands in his upkeep, but he breaks free with a Tendrils of Corruption on Telekinetic and then Extirpates them. On the subsequent turn, he casts Stronghold Overseer. Without Telekinetic to lock down his lands, I have three plans against that: (1) kill him with poison before he untaps, (2) mill him with Screeching Sliver, or (3) make one big unblocked Sliver with Firewake Sliver that slips through Overseer. Well, I get out Gemhide Sliver plus Firewake Sliver which allows me to quickly cycle through my deck. I draw Virulent Sliver and Summoner's Pact, use the latter to search for another Virulent, flip out my Dormants, and kill him with poison.
I am on the draw in game 3 and on my first turn my hand is this:
I can either go for the quick poison kill plan with Virulent Slivers on turn 1 and 2. Or I can go for the control plan with turn 2 Gemhide and turn 3 Dormant, using the Virulents to draw extra cards after Dormant is in place. I choose the latter, since I figured it would be unlikely to win on poison with the weak slivers in my hand; he just has to make an Augur of Skulls or Korlash to stop my beats. A turn 3 Dormant will easily win if he lacks removal. That plan pays off. I quickly get Frenetic Sliver out, and save my guys from his removal. I Delay a Damnation that he drew, and soon enough I flip out my Dormants and swing in with poison.
Round 5 – wereback201, U/G Tarmogoyf Aggro
In game 1, I have a fast start with lots of slivers: Virulent, Gemhide, Firewake and Two-Headed by turn 3. He makes a couple creatures of his own, while I add a couple more as well. Then I play Summoner's Pact for a second Virulent to swing in for the poison kill. But he has Snapback on Virulent, and blocks to stay alive at 8 poison counters. Then he untaps, Psionic Blasts my Gemhide and I lose because I cannot pay the Pact upkeep anymore.
In game 2, I get out a quick Dormant Sliver and start to draw cards as usual. I have the typical plan of assembling a critical mass of Slivers and eventually flipping out Dormants to alpha strike, but he has two morphs and I am afraid they are Vesuvan Shapeshifters. If he copies a Dormant, I can only win via Screeching Sliver since then I can't attack anymore. Eventually I have found enough Slivers and he still has not unmorphed any Vesuvan Shapeshifters. So I sacrifice both of my Dormants to Firewake Sliver (sacrificing is a cost; he cannot respond even if he has Shifter) and attack for the win.
In game 3, I play Screeching, Frenetic, and Telekinetic in the early turns. He starts with Tarmogoyf and 2 Call of the Herd. I add two Virulents for the lock plan, but he Snaps back Telekinetic.
I Gone an Elephant and double block another one with Frenetic and Virulent (killing it, and hoping to win the flips with damage on the stack). I replay Telekinetic next turn; he has no answer to it anymore, and quickly scoops.
Round 6: omniknight, UB Control
In game 1, I mulligan a hand with 4 lands, Screeching Sliver, Two-Headed Sliver, and Delay, because it has no action. I want Slivers that do something, and my 6 carder gives me turn 1 Terramorphic Expanse, turn 2 Virulent Sliver, turn 3 Virulent Sliver. He makes Shadowmage, but I play Two-Headed Sliver. He cannot find a removal spell and he is poisoned on turn 5.
In game 2, I have turn 2 Gemhide, turn 3 Frenetic and Virulent. He makes 2 Shadowmage Infiltrators, while I cycle Homing Sliver for Dormant. He plays Slaughter Pact on Dormant, I win the coin flip with Frenetic, and proceed to draw lots of cards including a Telekinetic Sliver.
I tap down his lands, and keep on playing Slivers until I find a second Virulent, at which point I flip out Dormant and swing in for 10 poison counters.
I went 9-4 over the course of two tournaments. I lost to Mono Blue Pickles, G/W Tarmogoyf Aggro, U/B/r Control, and G/R Wild Pair. They all had cheap removal against my fragile Slivers, including Desert, Serrated Arrows, Sunlance, Void, Damnation, Dead // Gone, and Rough//Tumble. Bogardan Hellkite is also hard to beat. The best way to tackle an assault of cheap removal spells is with Dormant Sliver and Frenetic Sliver; these are your MVPs. You just draw lots of cards and protect your slivers from removal. Eventually you find 2 Virulent Slivers, take out your Dormants through Frenetic, and attack with all of your guys. Summoner's Pact or Homing Sliver for Dormant Sliver as soon as possible, since it is the backbone of the deck. I beat 3 U/B Teachings Control decks, based on Frenetic plus Dormant interaction, and I would actually think that this is a good match-up for Poison Slivers. I also beat a couple green creature decks with Telekinetic Sliver.
I was surprised how often the deck does not play out as a beatdown deck. Even though it plays fast 1/1 creatures for 1 mana, these are mostly there to draw cards with Dormant, to tap permanents with Telekinetic, or to give mana with Gemhide. They also help to keep the mana curve low. I have only gone beatdown if I had a draw with 2 Virulent Slivers and a Two-Headed Sliver.
Would I recommend the deck if winning is your main goal? No, in all honesty I think that U/B/r/w Control or Mono Blue Pickles are stronger strategies, with more powerful cards, and a more consistent mana base. Furthermore, the current metagame full of Mono Blue Pickles and U/G Tarmogoyf Aggro does not seem right for Poison Slivers; these decks have too many bounce spells in Riftwing Cloudskate and Snapback, and spot removal in Psionic Blast or Serrated Arrows, as well as countermagic to mess up your plans. However, Poison Slivers is not the worst deck by far. It can still hold its ground against the top tier strategies; I found it a lot of fun and challenging to play; and another plus is that it is very cheap to build. It performed better than I had expected, and I think the best way to see what the deck is capable of is to play it yourself.
This is how I would play the deck now:
I made a couple updates to the original. I added a 24th land because I was often screwed, and cut some Forests for Islands to balance out the mana better. Furthermore, I cut a Screeching Sliver because it often did not do much and I always boarded it out. Furthermore, I moved the Harmonic Sliver to the board as the current metagame does not see that many artifacts or enchantments. I added two Telekinetics because it is good against every deck – often your main game plan – and a Psionic Sliver so that I can kill opposing Dormant Slivers in game 1, which can swing mirror matches and helps against Vesuvan Shapeshifters or Take Possessions that give their owners Dormants as well. I moved the Delays to the board, because I don't like it much against aggro decks, and there are too many of those. In the sideboard I tweaked the numbers a little bit, and cut the Shadow Sliver that never did much for me in favor of an Essence Sliver that in theory should be good against Red Deck Wins.
I believe that Slivers is here to stay; the deck may look horrendous on paper, but the vast amount of synergy within it makes it work!