Nice little flash like game!
I will join others saying the art and animation is nostalgic++ haha
You could make tons of levels, I know some people would gladly jump in and try them for hours! A little music and sounds would make things even better ;)
While navigating into your menu and games I thought about something I also encounter during this jam: menuing! The only use of mouse for your game is for the menu. Problem is, it is necessary. A little event handler to focus on the first button and set the navigation with arrows and space or enter would make your game feels better imo.
(Also try to align levels buttons ^^)
Good job !