Zombie (Including the Security Guard and HECU soldier versions from Half-Life:Opposing Force).

Fires the 5.56mm cartridge in full-auto, with a long revving up time.

XM214 Minigun - Unlike other weapons, must be picked up off the ground using E, and must be dropped before using another weapon.

Grenades now have to be individually loaded before firing.

M16 Assault Rifle w/ M203 grenade launcher - Fires in a 3 round burst.

Donators can use Golden Uzis, which do considerably more damage. Can be held in akimbo (duel-wield) for more power but a longer reload time. The medkit was also re-used in Garry's Mod but now players can heal themselves. Although a player can only carry a max of 100, the points regenerate over time.

Medkit - Allows you to heal other players by 10 points and revive non-gibbed ones for 50.

MP5 - Fires in Full Automatic, secondary fire zooms in.

Spore Launcher (Primary fire launches spores in a trajectory instead of a direct line like in Opposing Force).

Also, the secondary fire recharges the suit armor of players. Alt-fire releases a gigantic bolt of electricity that will hit multiple enemies, but uses up ammo quicker.

Shock Roach (Will start exploding when you have 30 or less ammo.

M249 Squad Automatic Weapon (new model).

M40A1 Sniper Rifle (increased damage, decreased accuracy without scope).

This only works if the player has at least 10 snarks.

For donators, secondary fire releases a chumtoad that hinders enemy ranged attacks and also poisons NPCs.

Satchel Charge (can be picked up or kicked).

This only works if the player has 10 grenades.

Secondary fire drops all grenades in one projectile, making a 'banana bomb'.

Tau Cannon (with less secondary fire recoil).

Black Mesa Crossbow (multiplayer version).

HECU SPAS-12 (secondary fire makes the shotgun shoot in full auto but with less accuracy).

Barnacle Grapple (New ability to rappel when used on teammates).

Pipe Wrench (with the ability to repair or revive friendly Sentry Guns).

Donators have a secondary fire that makes the crowbar more powerful against hostiles, but drains suit power.

Sven coop opposing force maps