ComBAT

The goal of ComBAT is to get to the highest stage possible by killing waves of bats. In the process, you can upgrade your weapon and heal.

WASD - To move the character
( You can double jump and even wall jump )
E - To interact with the shopkeeper
Mouse/LeftClick - To aim and shoot the gun

Credit - SoupIsGreat 
Don't forget to post your high scores in the comments!