[Varyon]

A few things to consider here.

The -10xHP = nothing left honestly doesn't make much sense. Sure, it's RAW, but consider the case of a human, and that same human raised as a zombie following a heart attack. If the human had 10 HP, then the zombie - being Unliving - should have 20 HP. If the human gets hit hard enough to take 110 HP of Injury, his or her body is "completely destroyed." If the zombie - who has the same body, but is unreliant on functioning organs - takes the same Injury, it is most likely "killed" (it's at -4.5xHP), but the body is largely intact. Determining the status of a body should look at where it would be if Homogenous, Unliving, and Living. Something that would be at -10xHP if it were Homogenous is truly and utterly destroyed - reduced to ash or splatter marks, shattered into tiny pieces, etc. Something that would be at -5xHP if it were Homogenous is too damaged to stay together. Something that would be at -5xHP if it were Unliving is too damaged to mechanically function. Something that would be at -5xHP if it were Living is too damaged to sustain life. So, to actually reduce an HP 10 human to a red mist or similar, said human would need to be hit with around 440 damage (that's the average damage of a ~126d cr attack).

For collisions, damage to both sides should be based on the mass of the smaller subject. A mack truck going at 100 mph (~Move 50) shouldn't cause more damage than falling at 100 mph onto a comparable surface, as in either case you're looking at the body being suddenly accelerated, changing its velocity by 100 mph (either going from 0 to 100 or 100 to 0). So, to reduce an HP 10 human to a red mist or similar, using average damage, said human would need to be involved in a Move 1260 collision, which is around Mach 3.4. Interestingly, this isn't too far off from what we'd expect from physics - I believe a collision exceeding the speed of sound in the material will utterly destroy it, and the speed of sound in the human body appears to be somewhere around Mach 4.

For attacks, what you're looking at is the pressure generated at the point of impact (and the follow-up). If it's high enough to go through the target, it goes through; if not, it pushes it back. A sufficiently-high-pressure punch will leave a hole in the target's chest (and arguably makes the damage type more akin to piercing than crushing). The Hulk swinging a telephone pole wouldn't actually pulp you unless the pole is being moved at somewhere around Mach 4 (probably higher, but I'm not certain) - but if there's enough force to go through, it may well bisect you.


Honestly, I think just keeping the first part in mind will handle your issues. Against an HP 10 human, 60 Injury will kill them, 100 Injury will mangle their corpse, 200 Injury will break their corpse apart, and 440 Injury will completely and utterly destroy their corpse. It's not strictly realistic - GURPS is not a reality simulator, after all - but should avoid logical disconnects.