Other than the restart button, I'd say you should add some way to tell how close you are to the target. Perhaps the sound could change as you get closer?
The sound actually changes as you get closer/farther from the target (it even shifts from left to right depending on your current position). Maybe it's not that noticeable... The game needs plenty of polish thou
Just played it again and it seems I was mistaken - the sound does change a bit. I guess I just feel it could be a bit more obvious where you're supposed to be aiming.