Sam Baughn's house rules for injury, shock and stunning in GURPS


  HP/2 damage in one blow = stun roll
  HP damage in one blow = stun roll -2
  2 X HP damage in one blow = stun roll -4
  3 X HP damage in one blow = stun roll -6
  4 X HP damage in one blow = stun roll -8

  ST/2 Crushing damage in one blow = DX roll to stay upright
  ST Cutting damage in one blow = DX roll to stay upright
  ST Crushing damage in one blow = DX -2 roll to stay upright
  2X ST Cutting damage in one blow = DX -2 roll to stay upright
  Etc...

  0 HP or less = Stun roll every turn

  - (1 X HP)  = Death check at HT
                All stun rolls at -1

  - (2 X HP)  = Death check at HT -2
                All stun rolls at -2

  - (3 X HP)  = Death check at HT -4
                All stun rolls at -3

  - (4 X HP)  = Death check at HT -6
                All stun rolls at -4

  - (5 X HP)  = Automatic death

  3/4 or more FT remaining = no effect
  1/2 - 3/4 FT remaining   = -1 to stun rolls
  1/4 - 1/2 FT remaining   = -2 to stun rolls
  1/4 or less FT remaining = -4 to stun rolls

make a stun roll vs HT every time you lose fatigue,
whenever you take more than HP/2 damage in a single blow,
whenever you are at less than 0 HP at the begining of your
turn, etc...

Stun roll missed by 1 = -1 DX/IQ/Skills/Attacks

Stun roll missed by 2 = -2 DX/IQ/Skills/Attacks
                         -1 Defences
                         -20% Move

Stun roll missed by 4 = -4 DX/IQ/Skills/Attacks
                         -2 Defences
                         -40% Move
                         DX Roll to remain standing

Stun roll missed by 6 = -6 DX/IQ/Skills/Attacks
                         -3 Defences
                         -60% Move
                         DX -2 Roll to remain standing
                         HT roll or pass out for 3d6 X 10 seconds

Stun roll missed by 8 = -8 DX/IQ/Skills/Attacks
                         -4 Defences
                         -80% Move
                         DX -4 Roll to remain standing
                         HT -2 roll or pass out for 3d6 X 10 seconds
                         Fright check

Stun roll missed by 10
or critical failure   = Automatic KO for 3d6 X 10 seconds

Recover one level of stun every second (unless KO'd)


High Pain Threshold [5/level]

Each level of HPT gives +2 HT to resist stun rolls.
Each level also allows you to ignore one level of shock.

Eg: Two levels of HPT gives +4 HT vs Stun rolls and allows you
    to ignore up to 2 X SHP damage in one blow.

Hard to kill [5/level]

Each level of HTK give +1 HT vs death checks.
Each 2 levels of HTK increases the threshold of automatic death
by SHP. HT modifiers follow the established progression (-2/SHP)

Eg: Ten levels of HTK gives +10 to death checks and increases the
    automatic kill threshold to -10 X SHP. At -8 X SHP you would
    be rolling against death at -14 (ie: HT-4) and against stun at
    -16 (HT-16 unless you also had HPT).