Cool idea!  I like how the player has to frantically switch their hand position all the time to get their finger on the new boost button.  One thing I'd suggest is to limit the jumping.  It was all too easy to just keep jumping and avoid all the obstacles, including new canisters that would change the boost button.

Good effort! =)

Hey I like you're take on the theme - always having to switch which key to press is a neat conceit. Unfortunately something was wrong with the timer and I would die randomly at like 3 seconds on it.

Hilarious idea, I love the randomly generated  key. Very original!