Scratch

I downloaded your project, and saw what happened. When i played it, it allowed me to switch levels, though, there were two things that i saw. First: you need a start block on [blocks]<forever>
                            <if><color[  ]is over[
                               <move(  )steps>[/blocks]
Second, the start blocks on the controls, are one time use when you set it up. You have forever blocks on there, which actually is preventing it from resetting, which results in it seems like it only effects it once.