Don't know if you're interested in bug report, but I was replaying some levels on higher difficulty today, and got a crash as the last level was loading. Screenshot here:
Launched into "Halls of Eternal Pain", selected 'Hurt Me Plenty', completed that level, and the game auto-launched into 'Sanctum of Torment'. I may have been clicking impatiently while it was loading :) Don't know if that would have had any effect.