All you need to make a good RPG is four pages out of Dark Heresy v1. Specifically, the critical effects tables. Like, that's literally all you need. Dig this:
Critical Energy Effects - Head:
7: In a gruesome display, the flesh is burned from the target's head, exposing charred bone and muscle underneath. The target is blinded permanently and takes 1d10 levels of fatigue. Also, roll 1d10. This is the target's new fellowship, unless their fellowship was already 10 or less, in which case nobody really notices the difference.
9: Superheated by the attack, the target's brain explodes, tearing apart his skull and sending flaming chunks of meat flying at those nearby. The target is no more.
10+: As above, except the target's entire body catches fire and runs off headless 2d10 meters in a random direction (use the scatter diagram on page 196). Anything flammable it passes, including characters, must make an agility test or catch fire (see special damage).
All you need to make a good RPG is four pages out of Dark Heresy v1. Specifically, the critical effects tables. Like, that's literally all you need. Dig this:
Critical Energy Effects - Head:
7: In a gruesome display, the flesh is burned from the target's head, exposing charred bone and muscle underneath. The target is blinded permanently and takes 1d10 levels of fatigue. Also, roll 1d10. This is the target's new fellowship, unless their fellowship was already 10 or less, in which case nobody really notices the difference.
9: Superheated by the attack, the target's brain explodes, tearing apart his skull and sending flaming chunks of meat flying at those nearby. The target is no more.
10+: As above, except the target's entire body catches fire and runs off headless 2d10 meters in a random direction (use the scatter diagram on page 196). Anything flammable it passes, including characters, must make an agility test or catch fire (see special damage).
Warhammer 40k TTRPG critical damage tables always live rent-free in my head.
The best ones are the plasma-related ones.