I played through the whole game and got gold medals on all the levels, and then I realized the "power accelerate" doesn't work with my Logitech G F310 gamepad (Xbox 360 type), which is what I used through the whole game.
I have been double tap-holding the RT on my gamepad and thinking I just couldn't tell if it was working or not and trusting that it was. My sister was playing through the levels and double pressed W and he lurched forward, successfully activating the power accelerate. :O (<- my reaction)
It worked with my gamepad if the FPS was around 30 (which happened upon unpausing if it was paused for a little while) but when it got back up to 60 I couldn't get it to work. I also tried remapping the buttons on my gamepad using third-party software and it worked that way if I didn't press RT down all the way down on the first of the double press.
Will there be an option to remap controllers and/or adjust double tap speed in the full release?
Otherwise, this is a very fun, great game and I don't think you should try to make it easier level-wise: Challenge is everything in a game like this. Greater control over the biker might be OK, but (in my opinion) everything works perfectly - except of course power accelerating (which I was able to get all gold without, so...). :)
P.S. What does "change camera" do? It seems to do nothing for me.