FYI: it happened to me a number of times that the game is stuck after 'killing' some enemies out of several enemies. For instance, a fight starts with three enemies. One or two succubi 'die' and the the game may be stuck. The game program is still running but interaction is impossible. Whether this happens seems to depend a bit on the sequence of eliminating the enemies.
It is in different scenes where more than one enemy is involved. Maybe even in all multi-enemy scenes. I made a screenshot of the fight against Asaris. Originally three enemies, two are 'dead', only Asaris is left and I cannot interact with the game anymore. The trick to get through that seems to be to kill them in the right order (so it is possible, but I did not yet try again).
