Blood effects (combined with corpse meats) were one of the biggest performance killers for older hardware, and even for newer one when playing with 4-6 players and scoring simultaneous kills. This update adds a more precise blood adjusting option that replaces the on/off switch. The default amount is now also lower, but the blood effect gets rendered in front of background tiles, so it is generally more visible, yet less straining for the CPU. If you still find the FPS dipping too much during intensive fights, try the light setting before turning the effect off.
If you want to use the old blood amount setting, choose "heavy" value for the "blood effect" option. The default "normal" is, as said, lighter than it used to be.
Full changelog: