Occasionally, a game will crash when fighting a Super Enemy. In those circumstances, I recommend the following advice, (particularly reducing the speed of the combat animations):

https://www.gamepretty.com/dicey-dungeons-how-to-fix-game-crash/

However, even this might not suffice when the game crashes against the final boss. In those circumstances, I highly recommend running the game in Windowed-mode, and using the following application:

https://github.com/AppPolice/AppPolice/releases

Use AppPolice to reduce CPU usage at the beginning and to increase it at the end. This enabled me to finish the game after numerous crashes.