Oh man was I bad at this, but it was fun!
My only feedback is that there were a few sheep silhouettes that spawned very close to the start of the arc and felt impossible to react to. It might have been nice to make sure that the gray silhouette always spawned with (eg) at least a quarter second's worth of travel time before the sheep hit it, so that there's room to react.
Otherwise, well done! I had fun, but I somehow found myself much more alert and jumpy afterwards, rather than than sleepy ;P