I really like the minimal mint-green look, the hand-written font and the step-by-step tutorial arrows. Restart and undo are easy to reach, which is great for a short 30 second level. The slingshot has no aim line or power indicator, so small pulls looked unresponsive and I could not manage to merge two balls. The timer also seems to run during the tutorial, and the scoring goal is unclear, so an aim preview and a paused timer at the start would help a lot.