Don't have much to say that hasn't been said, it's great and unique, and I'm addicted to it.
Appart from the gameplay, I think I'm particularly fan of the whole presentation of the game. From the CRT filter and pixel art to the joker card designs, how the main theme is altered depending on what's on screen, and the way everything is floaty and reacts to your cursor's movements. A lot of care went into it, and it's very pleasant to even just be in the game.