Hey this is cute and functional, a little buggy (left over enemies from a wave but the dialog starts as if its over, sounds clipping, lag on instancing though from my experience thats just a godot web thing). I like the different guns, I'm a machine gun kind of guy myself. The pixel art and writing for carl i mean the junk shop guy was quite charming.
Is there a way to see how much damage has been done to the junk shop? The failure message came out of nowhere I thought I was doing fine! With a little more info feedback to the player and some juice this thing would really shine, the premise is solid! Love the junkyard setting. Nice work!