Oizio is busted

Eclipse Dragon is really nice with Oizio. Like really, really nice. Dragon pays for Oizio, and Oizio replaces a dead Dragon. Or you can use the extra power to do a Torch/Annihilate/Ice Bolt + Oizio combo. These combos are pretty reactive, so the rest of the deck is built to deploy early but potentially game ending threats, then hold up removal/counters/draw/Oizio and mostly play on their turn. Oizio is also just a very good card (but you do have to build around it a bit). It's definitely one of the better promos they've released.

Oizio is super flexible, it can act like a better counterspell, a permanent madness, an ambush blocker/threat, or even just a 3 cost draw a card and play a 0/1 (that mode isn't great but sometimes you gotta do what you gotta do). Of course all of these require some conditions to be met, but this deck is very good at meeting those conditions. Oizio really helps enable a tempo/reactive gameplan because it's a good fast answer to a lot of things while also having the capability of being a legit threat. This lets you gain a lot of tempo advantages that you couldn't really gain with any other card. For example you can do stuff like kill an attacking unit and ambush it with Oizio to block and kill their other unit, potentially giving you an extra unit and killing both of theirs. That's a threat and 2 at fast speed kills for 2 cards and probably 5 power, which is pretty ridiculous.

Street Urchin has been super good. I mostly put it in because I wanted a threatening 1 drop so I could play a unit then hold up 2/3 power early in the game. That's been nice, but it turns out the text is also very good in this deck. The damage on spell is quite strong against a lot of decks since it can apply a lot of pressure for cheap, which means you have more power for answers while still being aggressive (which is the whole point of this deck).

On the other hand the twist effect can be very good, especially if you can time it so you use it right after they leave something on top with Scout (ideally before they know you have Urchin), or after they get a lot of Warcry or something like big Svetya. But a lot of the time I just use twist to get extra attack damage, or get a card to put in the market, which has also been very helpful. Even just using it as something to spend power on proactively without losing cards is good. Also it gets a lot better with buffs from Ripknife and Warleader.

Ripknife and Warleader have also been doing their job pretty well. Both of them demand an answer since they can snowball out of control, and they're cheap so you can play them early and start holding up answers. The unit buff is kind of a nonbo with Oizio, but if it gets big enough playing it without having something to transform into can be a good call. Although I've only had that happen once, with a 4/5 Oizio. Also, if something else gets buffed it's a more juicy Oizio target so I think it pretty much evens out.

Ripknife especially is good because it can force trades, and combat with a lot of deaths is where Oizio shines. A lot of times people will attack into it to trade and get it out of the way for their next threat. Oizio really messes this up since you can just replay either the assassin or their unit right before your turn.

Warleader is the generic beater/blocker of the deck, and it works really well. It's pretty much just stats, but it's a lot of stats that snowball out of control so they have to answer it. Also the self buff effect and the scaling passive work very nicely with Oizio.

Vara is really nice since so much of this deck gets neutralized by Aegis. She's also a good Oizio target sometimes, but you don't get her summon effect so she can be underwhelming. But if she gets deadly she's excellent for similar reasons Ripknife is.

Eclipse Dragon is the actual core of the deck. You don't need it to win, but it does help a lot. You'll almost always want to slam it ASAP, but don't be afraid to hold it back as a blocker.

Howling Peak has been pretty good, it's a bit slow but I can't really think of anything I'd want more. It's nice late game insurance and it gives a less unit based angle of attack, which is nice. Maybe Black Sky Harbinger or Dark Return could be better though.

Substitute is the flex spot in the market, but I've been liking it a lot since it's a really cheap way to permanently remove a unit from the game without triggering Entomb and the smuggler can block the Dino. Some other options I like are Dark Return, Mirror Image, Suffocate, Kaleb/Rindra's choice, Desecrate, or Permafrost. Desecrate is probably the right call but I really like Substitute so it's in for now. I think you want some kind of spot removal in that spot but maybe not, I'm not sure. All the other cards have been pretty useful I wouldn't replace any of them.

The deck is definitely super fun and kind of tricky. I've been having good success at masters 600-400, but I've thrown a lot of games. I think it's actually quite strong if you play it well, but that probably takes some practice.