Yep, UNDO works as a synonym for REWIND. Makes life easier for testing!
So ROLLBACK only comes into play when the game is over, correct? I'm presuming it asks you a question or something.
Viewing post in What is rollback and rewind?
Yes, enabling rollback only affects the lose_game or end_game commands, and allows the player to undo their last command after they have consumed the death (or end game) routine. It allows death to be used as a wisdom acquiring mechanic without being grossly unfair.
I do plan on adding explicit autosave commands in future too, so you can tailor auto-save points if your game (a reserved slot in the save game list).
There is a hidden (soon to be unhidden) system message called:
system_messages{
restore_from_autosave = Rollback?
}