Crowbar - 5hits x 20HP
Stunstick(Stun baton) - 3 hits x 10 HP, + confuse state(reversed controls)
Pistol - 18 bullets, -5hp each
AlyxGun - 20 bullets, -5hp each
Colt Python (357) - 6 bullets, -40hp each
SMG - 45 bullets, -4hp each, OR 2 grenades, -105 hp(areal) each (MODE 2)
Impulse Rifle (or AR2) - 30 bullets, -8hp each OR 1 ball - DEADLY (almost) - (MODE 2)
Shotgun - 6 bullets, -8hp each pellet, 7 pellets(mode 1), 12 pellets in 2 bullets(mode 2)
Annabelle - 2 shots, -60 hp each
Crossbow - 1 shot, -100hp
Grenade, -125hp areal damage
RPG, -150hp areal damage, HOMING.
And... Gravity Gun, 3 shots, 0 damage, but pushing player, if missed, shots do not reduce.