how about
Falling
the blockhead briefly flattens into the ground (as in, for barely even a fraction of a second) before bouncing back up again, snapping into place and splaying over on the ground
with normal falling (as in, not fast enough to kill) the blockhead flattens in a similar way but bounces up much less and flattens out much less
Electrical Weapons
the blockhead flashes black and white over a blackened 'electrocution' background. death from this kind of thing results in a blackened blockhead
Ballistic Weapons
the blockhead briefly disappears, then quickly reappears. when killed by this sort of thing, the blockhead flashes yellow, then splays out on the ground
* particularly high damaging ballistic weapons may get gibs, too
Vehicles
the blockhead ROCKETS into the air on death. according to the speed of the vehicle, this may be accompanied by a smoke trail
Explosion
gibs. the entire blockhead doesn't fall apart, but parts of the body detatch: as in, the legs may entirely detatch, or a single foot. the right arm may detatch or the entire upper body. etcetera
* in the case of explosives that don't kill, the blockhead begins to wave around in an unsteady fashion before he hits the ground.