You made a game like this in GZDoom? You absolute madman.
I think it's pretty neat. I like the art style, very Mega Man Legends-equse. It's kinda difficult, but I had fun though. I think you need a tutorial or something for the controls, I did not realise that you could repair the craft or that there was charge shot until I checked the controls on a whim. As for things you could add, maybe some additional weapons? Limited use bonus stuff you can pick up perhaps?
I hope you keep working on this, it's pretty cool.