Alright, I love this game. I audibly went "ooh!" when I read its description, haha.
The concept is simple but incredibly effective, and the way you all adapted existing game mechanics to fit its core idea is also quite interesting. Stuff like gears and hearts dropping where enemies die (aka where most of the bullets are) is a great decision. Being able to push and block enemies is also a nice touch.
In regards to the overall presentation, I really liked the game's polish, aesthetic and SFX, though the same can't be said for its music. It's not bad, per say, but I didn't think it fit the game's theme.
All in all, this is a very strong contender.