Blood was the best! A friend and I used the Build Engine editor to create a Blood level that was just traps that killed the innocent NPCs. Buttons to release monsters, drop people into lava... Now that I write this out it sounds kind of F'd up! It was fun learning how to make it all work though.

The sound effects were particularly great in Blood!

The whole body dismemberment phase of PC gaming really died too young! PUBG could benefit from some!

Clive Barker's Undying was a nice gory game from a few years back, some interesting mechanics as well with the visions and such.