I also seem to get crashes, and I've discovered a repeatable crash when interacting with the para koopas. If you knock any of the flying ones out of their shells with the ptooie on screen the game will crash. I also get crashes with two or more ptooie on screen as Amomario said below.
I wasted a lot of time trying to set the dynamic version of these sprites. I was excited to use these in my demo, but I'm about to release it, so I'm gonna reserve your sprites to use them in the full version. Thank you so much for making things easier for noobs like me haha.