The run key - why is it even there?
Perhaps I'm being overly cynical here for such good controls, but the run key is quite a confusing matter for me. I used it twice or so in world 1 on my first playthrough, only in the levels that required it, until I got to world 2, where I kept the button depressed throughout the entire next couple chapters. Which leads to a question: why is the key there? There's no advantage to walking rather than running (that I've seen so far; correct me if I'm wrong), and my finger is quite sore from just holding the key down constantly. I have half a mind to map it to left, right, and jump, just so I don't have to bother with keeping the button pressed constantly.