Build 42 Combat — Muscle Strain, Discomfort, Body-Part Gunplay, and Explosives

Build 42 killed the Build 41 kiting loop: melee now costs muscle strain, heavy armor costs discomfort, and firearms reward aimed shots to specific body parts. The official design intent is that "shorter fights feel safer — rest matters more, better weapons matter more" (community-reported from the veterans' guide, and visible in every formula below). Verified mechanics from PZwiki's Health and Discomfort pages plus the official Build 42.20 feature overview. Checked 2026-08-04.

Muscle strain: the math that paces every fight

From the Health page's muscle-strain section:

• Weapon skill: at level 10 in the relevant weapon skill you take only 10% of the normal fatigue — each level cuts strain by 7.5%.
• Strength: level 0 takes 150% strain; each level reduces it 10%, reaching 50% at level 10.
• Crowd multiplier: strain scales with zombies hit per swing — 2× for two zombies, 3× for three. Swinging into a packed line is an endurance suicide.
• Swing cost: 60% of the weapon's weight plus 120% of its endurance modifier; a two-handed weapon held one-handed adds 4/15 of its weight again, while using both hands halves the strain increase. Fatigue lands hardest on the right hand, forearm, and upper arm (250%).
• Over-encumbrance level 2+ converts its health damage into muscle strain — fighting overloaded is doubly expensive (heavy load moodle).
• Shoves cost 0.15 strain, stomps 0.3; shooting applies strain to the arms, but full-auto fire halves the muscle strain of recoil.

Practical read: fight in short bursts with skilled weapons at full rest, disengage before endurance icons appear, and never swing through three zombies with a heavy one-hander.

Discomfort: why max armor is dead

Clothing with a discomfort value builds the Discomfort moodle, and wet/hypothermia/hyperthermia moodles each add +10% per level. Verified item ratings:

Levels escalate from "a little uncomfortable" (20–40) to vocal misery (60–80+). Community-reported from the B42 balance cycle: discomfort was retied toward stress rather than pure unhappiness, Desensitized characters became immune, and a Discomfort Modifier sandbox option was added — tooltips now show discomfort plus run/combat speed costs. Build a light "base chores" kit and a heavier raid kit, and swap deliberately.

Firearms: aim for the part that matters

B42 shipped a new aiming system with precise location targeting, affected by panic, stress, and Aiming skill (official). Community-reported specifics: headshots matter more, limb hits matter less, and awkward vertical shots behave better. Other verified changes:

• New guns: L92 Lever Action and JS-3T Tactical Shotgun; firearm loot distribution reworked to match Knox Country's gun culture, with civilian/police/corrections/hunting/ranch/military loot contexts.
• Shotguns no longer train Aiming per pellet; jamming eased via sandbox multipliers; .223 folded out with the varmint side moving to 5.56.
• Loot comes as three separate checks: gun, ammo box, and magazine.

Weapon parts and sharpening

The melee part system (official): some weapons track handle condition and head condition separately, plus blade sharpness; heads can fall off entirely. Broken weapons remain usable as crude clubs, and a broken spear still fights weakly. Maintenance reduces per-hit condition loss; whetstones (including the improvised variant) sharpen blades — keep one in every kit, and check tooltips before assuming two same-named weapons are equal (forging replacement heads).

Explosives: three jobs

The remote trigger needs a crafted trigger, scrap electronics ×2, duct tape, and Zapper! magazine or Electrical 8 (build at Electrical 2). Zombies ragdoll when hit by gunfire, vehicles, or explosions (official). Noise discipline matters more than in B41 — gunshots and blasts carry farther into the new heat-map population (map guide).

Zombie changes that affect every fight

Community-reported from the balance cycle: fences bend and break (wire fencing especially), a sandbox option gives zombies a percentage chance to open doors, turning and stagger behavior improved in all directions, and crawlers target better. Perimeter defense needs active repair now, and indoor clears are handled separately from the outdoor heat map.

Verified on 42.20 · Last checked 2026-08-04

Muscle-strain formulas and stomp/shove/shooting strain from PZwiki's Health page (42.15.3 stamp); discomfort values and levels from the Discomfort page; location targeting, weapon parts, ragdoll, and new firearms from the official 42.20 feature overview; pipe-bomb data from PZwiki. Body-part damage multipliers, recovery-rate numbers, and the discomfort-to-stress retie are community-reported or unpublished — exact headshot numbers in particular remain unverified.