Thanks for your reply, it moved us a lot since we only recently learned to make video games. In fact we didn't had time to implement a real "end" in the game. So even if you find the 12, nothing happens unfortunately. We focused on having something that make the player to want to understand how the world works. We use collectibles (the mushrooms) because it was simple but with a little more time we could have done something else. For example, a big puzzle in several steps like a big escape game.