I don't know how "fixed" the game design, on casey's side, already is, but maybe we could collect all kinds of ideas here, where he could pick from. We already know it will be inspired by games like Zelda and The Binding of Isaac, the ideas should fit into a game of this type.
So here is little thing I had in mind. The "making of" Handmade Hero, is mainly focused on education, how to write code and etc.
The idea is a short "code typeracer" challenge, for example in a dungeon, where you can win an "extra cool bonus item". Extra cool, because you had to use a keyboard instead of a controller. The code, that has to be typed, could also have an effect on the game and/or is kind of pseudo code to solve a puzzle in given time. The time needed to win the race, gets longer with each try, so everybody can win.
In one of the earlier streams someone suggested almond milk as powerup. Personally i think thats a great idea.:) Also having different colored bottles would be nice. :D
So what do you people have in mind?