Killzone features a multiplayer called Battlefields which featured 6 game modes, 8 playable maps, and almost all weapons used in campaign.
You can play as two teams in multiplayer.
- ISA - A standard looking bald ISA soldier. He's equipped with a M82-G Assault Rifle and a M4 Semi-Automatic Pistol
- Helghast - A standard Helghast soldier equipped with a StA-52 LAR and a IvP-18 Tropov Machine Pistol.
Killzone has 8 unique multiplayer maps. Maps with * were reused and redone in Killzone 2 because they were voted as fan favorites. Not all maps were playable in every game mode. Some maps were not fit for that certain game mode if its not playable.
- Canyon Crossing - A snowy canyon connected by a bridge.
- Vektan Slums - A map based on the slums in the campaign.
- Core Shaft - Part of the ISA headquarters.
- Park Terminal - A map greatly based on the Park Terminal from campaign.
- Orbital Station - The SD Platform orbiting Vekta.
- Southern Hills* - A open map with a large Hilltop Base situated at the center.
There are 6 multiplayer modes. For modes which are played with teams, there is a maximum amount of 8 players per team, 7 if the team only has bots. Game mode options can be changed.
- Deathmatch - The only game mode that doesn't use teams. You start at a random part of the map and try to be the first with a certain amount of kills.
- Team Deathmatch - You spawn at a random part of the map and the winner is the first team that can achieve a certain amount of kills.
- Domination - Several markers are placed across the map and can be captured by getting near it. A team that has control of a marker will slowly get points. The first team to acquire a certain amount of points wins.
- Supply Drop - Several crates of supplies are found across the map. You need to pick up the supplies and bring them to your base. Having supplies will slowly earn you points. The first team to acquire a certain amount of points wins.
- Assault - One team attacks the other team in an attempt to destroy two generators. If the attacking team isn't successful in a certain time limit, the defenders win.
- Defend and Destroy - Both teams have two generators that can be destroyed at their base. The team that destroyed more of the enemy's generators within the time limit wins.
Weapons - You could only carry 3 weapons with you at time. You also start out with 3 M194 Fragmentation Grenades. There are 15 weapons that you can pick up.
- LS13 Shotgun
- M224-A3 Heavy Support Weapon
- M66-SD Submachine Gun
- M327 Grenade Launcher
- M404 Missile Launcher
- BLR-06 Hadra MRL
- BP-02 Pup Grenade Launcher
- Pnv-3 Siska Squad Cannon
- StA-3 Stova Light Machine Gun
- StA-52 Sniper/Light Assault Rifle
- For some weapons, there is no reload animation seen by other players, only the player that reloads his/hers gun can see this animation.