Ah yeah, I had no clue about the time bubble ability. And the fireballs for puzzles makes sense, especially with how you can freeze them in place. I found that pressing M also gives you free boost power (for testing purposes I'm sure).
Just playing around with the builder is pretty fun on its own. I have found two more crashes though. The first one happens if you use time bubble and shoot multiple fireballs upward. After unfreezing time, the stack of fireballs falling down can cause the crash. Second one happens sometimes when trying to create really small and/or thin polygons in the builder:
