7-2 Felnport recursion

Wincondition: Recurring Nightmare over multiple turns, but standard unit beatdown is also possible if the opponent doesn't have enough blockers.

Use Spellshield Architect to protect the Gorgon Fanatic and the Nightmare (especially important if the opponent has fast silences like Desert Marshal, Purify, Bring Down), but it's also helpful on Inquisitor Makto.
Haunting Scream helps a lot with Gorgon Fanatics (improving later Dark Returns significantly), but it also works well with Recurring Nightmares (since they bounce back into your hand with Infiltrate instead of being sacrificed at the end of the turn). You can get some utility out of it with Spellshield Architect and Stonepowder Alchemist, and if you are at 8 power, you can also use it on Feln Bloodcaster to ultimate it immediately.
The various lifegain cards (Bloodletter, Gorgon Fanatic, Shield Bash, Stonepowder Alchemist) were sometimes relevant because with Recurring Nightmare plan puts in quite a race against some decks, and you have to use your removal to allow free flying attacks.

Removal suite: 3xBring Down (good against Flyers and Champion units), 3xEilyn's Choice (also protects against Harsh Rule), 3xSlay, 4xFeeding Time (great against recursion).

Flex slots (AKA I have no idea what I'm doing): 2xBloodletter, 1xTrickster's Cloak (both weapons suffer the downside of my units moving a lot between the battlefield, my hand and the void - but when put on Spellshield Architects or Feln Bloodcasters they were fairly useful), 2xShield Bash (can help pushing units through or prevent some damage, but even at 3 cost it's too slow), 2xDuelist's Blade (targeting face wasn't as prevalent as I expected, though once it did me great service blocking Steward of the Past's Summon effect), 1xKosul Brigade (AKA I have this new shiny card I wanted to try - while 13 attack for 5 mana is no joke, costing 3 cards when the only draw-engine in the deck is Gorgon Fanatic is a real downside, especially because by the time they came down the 8/8 Bear was just going to suicide itself into blockers, killing two or three at best).

The deck could be probably better optimised (I tried building it using only multi-faction cards, but couldn't skip Dark Return - that's why Permafrost and Finest Hour are missing), but I didn't want to craft too many cards for it, I used only what I had. I also tried to be very light on the influence requirements due to lack of good fixing.
(The primary idea was to abuse Haunting Scream with the cost reduction of the event, but the only good hit at 5-cost was Makto - who does not spend a lot of time in the Void. I was also hoping that Revenge from Stonepowder Alchemist would be reactivated after it dies a second time, so reanimating it with Scream would put it back in my deck when it dies - I did not have an opportunity to verify this, but Revenge was grayed out when the unit was in the void, so I wouldn't expect it to work that way.)

Out of the 5 leaderboard runs, I had a 7-2 (hence writing this), a 6-3, a 3-3 and 2 even worse (can't remember exactly) - but after each run, small modifications were made. At the time of writing (28 hours before the event ends), this puts me at place 577 on the leaderboard.