Awesome game. The art and models for the game are great! The gambling mechanic is pretty cool and having a negative effect for when you lose is a cool idea. I think having another mechanic for the player related to the movement or roulette ball and having more enemy types would make the gameplay more interesting.
Since you're in first person, there would be times where you're focused on one group of enemies and there would be more behind you. I think adding a SFX for the enemies as a way alert the player would be good.