Timesplitters had a good lot of funny dying animations, like when you'd burn a zombie to death and it would continue walking but it's legs would slowly give way, causing it to slowly descend before it's whole body slumps to the floor.
Or that one for when you get shot in the ballz and roll backward onto the ground like a dead insect.
And nothing's more fun than sending a grenade hurtling towards a group of enemies and watching them all fly in different directions before returning to earth in a heap. I like the way the animation changed depending on which direction the explosion came from.
In terms of gibs, the injector would cause your enemy's screen to stretch(if human), with their body expanding at high speed, if you loaded enough darts into them they'd explode in a bloody mess of gibs! Headsprouter would gib, too, in story mode, causing damage if you were too close!
Oh, yeah, and there was one in TS1 which occured when an enemy would fall from a high place, they'd scream and fall, as you'd assume, but in TS3 at one point in the game, they expanded upon it, in the level "You take the high road", one of the guys you'd shoot off one of the balconies would fall in the same way as in TS1, but they added more to the slapstick misery. The guy lands on a fence below, on his crotch. As he gasps for air in shock and pain, he falls again, into the abyss below Kronia.
Truly they are the masters of death animations.