Hello, some feedback for you :)
When shooting, the camera shakes which is nice. But I notice that the room map also shakes with it. As an update, why not making it so only the camera shakes. This would make it feel a lot nice I think
The shop interaction was a tiny but confusing at first but that wasn't a big deal, one you know you know. The price for health is a little to high I though. First time around, I got very damaged by the 3rd wave but couldn't afford any health. Maybe make health cost around 50-100 coins.
Love that you've added sound effects and music. For small games, I sometimes can't be bothered haha. Keep up the good work :)