Type in all cheats in the Quake II console (use ~ key to bring it up).

Code - Description

g_unlimited_ammo 999 - Unlimited ammo.
give all - All weapons, items and full ammo.
give adrenaline - Adrenaline.
give airstrike marker - AirStrike marker.
give ammo - Full ammo.
give ammo pack - Ammo pack.
give ancient head - Ancient head.
give armor - 200 body armor.
give armor shard - Armor shard.
give bandolier - Bandolier.
give bfg10k - BigFu*kingGun10k.
give blaster - Blaster.
give blue key - Blue key.
give body armor - +1 body armor.
give bullets - 50 bullets.
give cells - 50 cells.
give chaingun - Chaingun.
give combat armor - Combat armor.
give commander's head - Commander's head.
give data cd - Data CD.
give data spinner - Data spinner.
give environment suit - Environment suit.
give grenade launcher - Grenade launcher.
give grenades - 5 grenades.
give health - 100 health.
give jacket armor - Jacket armor.
give machinegun - Machinegun.
give power cube - Power cube.
give power shield - Power shield.
give pyramid key - Pyramid key.
give quad damage - Quad damage.
give railgun - Railgun.
give rebreather - Rebreather.
give red key - Red key.
give rocket launcher - Rocket launcher.
give rockets - 5 rockets.
give security pass - Security pass.
give shells - 10 shells.
give shotgun - Shotgun.
give silencer - Silencer.
give slugs - 10 slugs.
give super shotgun - Super shotgun.
give weapons - All weapons.
god - God mode.
noclip - No clipping mode.
notarget - Enemies won't see you.
sv_gravity ### - Sets gravity to ###.

Tips:

Type in all cheats in the Quake II console (use ~ key to bring it up).

cl_footsteps 0 - turns off footsteps

sv_gravity 1000000 (makes it to where you cant jump but die on falls unless little falls)