Nice little twist on platformers! I'm sure you could push this very far with some voice acting. Maybe don't limit yourself till the end of a level to add new things, and make it so the player has to choose between features and they can't buy everything in a single run. This reminds me of DLC Quest actually. Other than that, the things I wanted to comment about have all been stated before. It has a lot of potential, I'm glad I tried it :)