Remarkable: Super satisfying gameplay, excellent organization of scenes and code.
Needs Improvement: Initially I didn't see that I needed to hit enter to advance to the next level - the flow of messages in the console made that a little unclear (there was lots of other activity in the console). I also found it a bit frustrating how long I had to wait to fire the next cannonball, and there was no way to see how long it was going to take.
Successful: The detail of objects spawning in not *exactly* where they need to be so they sort of settle into place is really neat (whether or not it was intentional).
General: A perfect balance between simplicity and complexity. Like Angry Birds, Boom Box, and other games like this, you could build a ton of levels based on just the foundational "blocks".