Looks really good visually and the sound effects are excellent too. I also appreciate that you added in control remapping. The gameplay itself is very fun. I especially enjoyed using the flamethrower and getting up close at enemies to kill them.
My main gripe is that the overall goal of the game is too confusing. At first I wasn't sure what the coins did, or why I wasn't dying from getting hit so often, until I replayed the game several times. A quick tutorial or a guide screen would've been really helpful. Once I figured out the game's win condition, I still found it to be too difficult to win. I think instead of losing all the coins on the screen when getting hit, you should just lose a handful from your already collected amount. It will make fulfilling the win condition much easier.
Overall, great job on the game! I had fun playing it.