I hope you don't mind some critical feedback but I think there are a few things that could make this experience more enjoyable. Easiest one would be to ensure the BGM continues. Keep it on loop on a dedicated audioStreamPlayer. The footsteps were kind of rough. You could get away with using one foot step sound and pitch shifting it each time. Preload the audio so the game doesn't stutter on the first shot. Attach some distance variable or timer to the projectile to remove them so they don't continue on forever. I can clear the whole game without walking. I like the expanding play area idea. I get deadlines are rough. Keep at it and you'll get there. Good work.