Nice game for your first time, but it's pretty frustrating. Firstly, if you're going to have some platforming in your game, add coyote time and maybe jump buffering to avoid aggravating the player. And unless you want your player character to look tiny in comparison to the rest of the sprites, resize the pixel art in the canvas, and not in Godot. Btw the player character is hard to see because everything is black and white (which does make the enemies stick out). Also, tell the player the controls somewhere, it took me way too long to realise the player had a gun.