Alpha 11 on Windows 7; paid, with tiles.

I possessed a sleeping raven, then I think it fell asleep again, or it stayed asleep and the game asked me if I'd like to unpossess the raven because it was sleeping.  I hit yes, but I stayed possessed and the game stopped responding to input.  I saved and quit, and when I tried to load the save, it shows one of the white masks, then the game's title and then hangs, requiring a force quit.  I'd attach the save, but even compressed it is too big for the forum (max 4M per file).  Here is a link: https://drive.google.com/file/d/0B_snSKcb4wIycUVLbzIzWGpDam8/view?usp=sharing

Perhaps you should look at the way Nethack4 (http://nethack4.org/) (and others) do their saves, which enables them to roll back in the case of a desynched/broken save.  Because of this bug, my entire game is ruined.  Luckily I wasn't far in, but it makes me hesitant to play again if individual bugs don't just make me lose progress, but destroy the game entirely.