Thank you such much for playing and your kind words.
The Demo system is a bit stunted and jarring. In the main game everything is tied together via an overworld that matches the styles and graphical themes of levels for each world. However, your feedback is still very valid. Especially concerning polish and adding some "juice". I've tried to make games before and I spent forever on developing systems and never released anything, so I focused more on content than polish in order to force myself to release the game.
I'll look into improving the game and perhaps making the demo more representative of the full game experience.