Easier levels hints:
-Purchase the Rewinder and always upgrade it often. Use it to destroy the waves before they reach the end ball and get more part coins at the end of the level. Use them to purchase other upgrades.
-Remember where the colors are on the fixed puzzles/control parts when a level begins. Shoot as many as possible when you can.
-Focus on the fixed puzzle/control parts unless the moving waves are close to the exit.
-The shrinking bar at the bottom of the screen indicates when the next wave will arrive.