This game is really fun! My laptop's trackpad wasn't working too well, but the touchscreen was, which I think actually elevated the experience. I had to tap enemies on the screen to fire. I actually had a lot of fun playing this! I'd like to see you take it further, if you have any desire to. The mechanic of building your chamber of bullets is really cool, great for roguelikes. This would make a great mobile game
If you added like sequential synergies to the chamber (bullet that makes enemy take double damage on next hit), then you could put that -> sniper for a crazy build. Could be a lot of fun.