Wow! Thanks for this in-depth review. Yes, everything that doesn't seem right is because I couldn't do it before the deadline. I had a plan of adding more levels/content too but then I cut them off when I realized that I'm running out of time.
The yellow hooligan's projectile (the grenade) hits an entire column.
The enemies becomes invincible when hit so that the player can't spam shooting.
I also found a problem with UI. Some text is not visible on some screen resolutions.
Thanks for the video suggestion, I appreciate it!