This game really is a nice idea and i like how the game only got harder and harder overtime, however it feels very much unfinished as you've said the movement feels pretty bare and the game kinda is impossible when you're left with only 1 movement option, would love to see this mechanic fleshed out more tho as the concept is very sweet.
The game however as a game is clearly unfinished so it would be tough to compare this with more feature full submissions. i would like to see this project continued tho with the jam 1 script nature and see how things might turn out. very well done. very impressed its all 1 script