Completed the whole thing, had fun with it.
Only real quarrel was the aiming system which got a bit weird when trying to do gun-jumps. Maybe make it so that when youre in the air, firing downward always shoots straight down, just so on longer jumps you dont have to press right-down > down > shoot > right-down to keep momentum.
Another thing is that I found myself using the scatter most of the time just because it was better than all the other guns at jumping. Might want to have a bit more variance between the three. For instance, have the scatter excel in vertical motion, the machine horizontal, and the ultralight somewhere inbetween.
Other than that, good concept. Feels very cave story-ish.