Use the arrows to move and the space key to boost.
Oh cool, so it doesn't work on whatever version of Scratch we're on now, the player just clips the background to the wall. It used to be cool, though, take my word for it. The assets and scripts are pretty cool, nab those if you want to use 'em. I just took the sprites from RHYS anyways. Released in 2014. Made in Scratch 1.4.