The routines SaveKernalZP and SaveGameZP both write to $00 and $01 (STA $02,x writes to $01 if x=$FF). I think this is not intended but switches the datasette motor on and might cause other side effects.
Yeah you're right, there's another bug where I copy what ever is in GameZP to the actual ZP upon launch, when I intended to just back up the Kernal ZP at that point. It just happens it doesn't crash this game but it did the next project. Will fix!
