Fleshed out and understandable!
I like the gameplay loop! While it's a bit simple, it's still fun! Something to think about is that the player will be doing the same thing the entire time. There's a clear dominant strategy, and nothing in the game ever changes that up. That would be fine if the game-loop was short, but game take awhile to get through, so something needs to change up how the player feels.
I would've liked to see more mutations other than just weapon adjustments. Player movement, auras, additional effects... If you're going for a Vampire Survivors vibe, look at what is interesting about Vampire Survivors.
Clear visuals and audio. Well done!