**Fixed a save bug that could wipe your progress.** If your save file was

damaged, the game failed to read it, started you at level 1, and then wrote

that empty run over the file twenty seconds later. A save that cannot be read

is now left strictly alone — the game turns saving off for the session rather

than touch it — and a backup copy is kept from the start of your last session

in case the main file is ever unreadable again.