You have something with potential, here. I think it needs refinement, touch-ups and fixes here and there, but otherwise it's a good effort on your part!
A few things I noticed:
- A lot of the details, especially text, appears quite blurry and out of focus on a smaller frame/screen; text is much easier to read when going full screen.
- To avoid continuous jumps while holding down the jump key, you'll want a value that is set when you hit the jump key, ignores attempts to jump if the value is already set and it is cleared when the player lets go of the jump key (Used to run into a similar problem, myself; that was what I went with for my solution).
- Enemies shoot through walls... grr...