Hiya,
Thanks for responding - I appreciate it, as I don't particularly want anyone to have a bad time with this.
That said - I have to admit I'm completely baffled by this one. There's not a huge difference between the games first boot and restarting it, mostly just the first time you start it creates a header file for each of the save slots, then checks for any completed stage files so that it can total up the number of collected coins. I'm guessing it's not going to be the 10 second "I think your game is stuck in a loop" Playdate OS crash.
Does the game still crash when restarting if you exit without having created a save file?
Does the game still crash when restarting if you exit immediately after entering your name (whilst the opening sequence is still playing), or is it only if you have played a stage or two first?
I've uploaded a second version of the game labelled as Debug above - if you have time (no pressure - don't really want to put anyone out) could you give that a try a tell me if it's still crashing and reporting an error or not? I've moved some of the initialisation code in the hopes that it may report a proper error message if things aren't being done at boot time.