Disabling writes during "wipe" and "first load" is not quite semantically what we want, it's writes during read we want to block. This happens because turning the music on or off tries to save the state, and it's easier to just ignore that persistence request than to rework the music code so it doesn't. "wipe" and "first load" are when we're actually reading (and enacting) state, but it's the act of reading rather than those two acts that should block writes.
It is also unwilling to write until it's done its first read, which I think is a feature; it makes it harder to accidentally blank out the player's data.
Saves the music flag, the last level the player played, and the furthest level reached. Loads music flag on launch. Title screen starts on most recent level played; when in "release configuration" the title screen will only let the player pick levels up to the maximum reached through gameplay, but right now this is replaced with the 31.
Save file can be wiped by holding the down arrow at the title screen.
