Impressive that you added that much content in pygame in 3 days. The encounters felt intense and the game had a nice style.
Some suggestions:
- You should keep working on the shotgun's firing and maybe add an ammo system (was the UI originally meant to do that?) or add audio/animations to make it more satisfying to fire
- Acceleration-based movement
- Audio/visual cues on win/death
- Better explanation on how to pass a level
- Bind W to jump
I hope you'll keep improving the gameplay and refactor the code to make it more readable and updatable. Again, the workload was probably insane, especially with working solo and without a game engine. Good work!