The game that started off a sudden craze and lots of clones, Vampire Survivors 1.6 is out now adding in local co-op along with moving over to the Unity game engine.
The developer worked designing slots for the gambling industry before.
Part his game mechanics are really addictive as they are similar to how people gets addicted to gambling (lootboxes, coins, spins, colorful lights, win animations, sounds similar to slots machines).