GURPS 4 House Rules
Basic Set Chapter 10: Combat
HR10.1 Maneuvers - B363
When using the Aim or Concentrate maneuvers, you must decide whether to defend against guns or other fast ranged weapons as soon as it is pointed at you, which is before any rolls to attack. Waiting to see if your opponent misses or pulls the trigger rather than aim would be too late.
HR10.2 Defending - B374
You are considered to be always ducking and weaving against firearms you can see unless executing All-Out Attack, which permits no defence, or Aim, Concentrate, or Attack whilst claiming an Aim bonus as this would ruin the maneuver.
You cannot block with oversized shields, which are essentially portable cover.
HR10.3 Optional Rule: Extra Effort in Combat- B356
You must make a Will roll as well spend the required FP. On a failure, the FP is wasted for no effect.
Other extra effort can be attempted at particular times.
Crawl On: Whenever you're incapacitated but conscious, you may crawl at 1/10 Move or walk leaning against a wall at 1/5 Move for 1minute without risk of falling unconscious. If you aren't already leaning against a wall, you need handholds to drag yourself up. These are Move maneuvers but no defence rolls are allowed. If you fail the attempt, you must wait 1minute before trying again. Attempts cost 1 FP.
Run on Fumes: Whenever you're at less than 1/3 HP or FP and aren't incapacitated at the beginning of your turn, you may ignore the Move, Dodge and ST penalties of low HP or FP (see B419 and B426). If you fail the attempt, you suffer these penalties as normal. Attempts cost 1 FP.
Stay Up: Whenever you're required to make a HT roll to stay conscious or avoid knockdown and stunning, you may forego the HT roll as if you succeeded. Apply the same modifiers to the Will roll that would apply to the HT roll. If you fail the attempt, you must make the HT roll as normal. Attempts cost 1 FP.
HR10.4 Cover - B407
Oversized shields are larger than a man and are essentially portable cover. If a viewport is installed, a one-handed weapon can be fired whilst only exposing the weapon arm and hand.
10.5 Mortal Wounds - B423
You are mortally wounded and instantly incapacitated but not slain if you fail the HT to avoid death by 4 or less. If you failed by 1 or 2, you may make a HT to stay conscious. If you failed by 3 or 4, you are also rendered unconscious and will die in 4 minutes without resuscitation (B425).