I'm glad that you really enjoyed the game.
I had a few things in mind which I wanted to try - for instance, in the last level, I wanted to add bullets which moved vertically (bottom to top) and yes, I had in mind to add more core-in-game controls which can be used as platforms.
But at the end, I made this prototype within 12 hours... still yes, you pointed out some good feedback and I really appreciate it!