LOS ANGELES--Killzone: Liberation is a follow-up to the PlayStation 2 first-person shooter, but the PlayStation Portable version opts for a third-person viewpoint and cooperative play. The game shown at E3 is 60 percent through development and offered both single-player and multiplayer levels. We delved into the three single-player missions available, which offered a taste of solo and cooperative play with the artificial intelligence, plus the ability to drive a tank.

　　Starting the single-player Buddy Beach Head mission, we were offered the chance to use one of 10 weapons, but only three of them had been unlocked so far. Weapons are found as you play through the game, and you can use credits to make upgrades. We chose to take the STA-52 Assault Rifle into battle, but we really wanted to take one of the unlockable shotguns from the full offering.

　　You control your soldier from a third-person perspective with the analog stick and use the D pad to issue commands to the other soldier. Around half of the missions will feature an ally that you need to give orders to, although there's never more than one troop to control. You can heal this soldier at any time, but if you let him die and do not resuscitate him within 20 seconds, you will fail the mission. You press up on the D pad to bring up the command menu, and then you can send them to a number of strategic positions in front of you.

　　Killzone: Liberation demands a tactical approach to combat, as we died more than a few times when taking the gung-ho approach. The game rewards stealth play, and you can see from the color of the enemy's visor whether they are aware of your presence. The AI of your cosoldier and the enemy troops is commendably good--they will take cover and attack from a distance if the opposition has the advantage. Enemies will also fire at exploding barrels if you are close to them, which will explode and cause damage.

　　Combat is based on an automatic lock-on system, but you can tap both shoulder buttons to change to another enemy manually. Crouching gives an improvement in accuracy, and you can also toss grenades from behind cover to kill an enemy or force him out of his position. You can also perform melee attacks on crates, which will wield new weapons and power-ups. Caught in the middle of a battle with a couple of enemies, we shot at a crate with a spider mine inside. This automated explosive headed over to the nearest enemy and exploded on impact, killing one of them and injuring the other.

　　The troops that offer support in cooperative play will also have different behavior, with some being more aggressive than others. Some missions will be played solo, and others, like the Tank Battle level that we played, offer vehicular combat. The full game will also feature hovercrafts, but the tank shown at E3 controlled particularly well. It was big enough to crush scenery, so you could plough through barricades and run over enemies. You can also operate a turret with the shoulder buttons, but being such a large object, it is vulnerable to rocket attacks. It only took a couple of shots to set the tank on fire, and we needed to evacuate before it blew up with us inside it.

　　The story of Liberation immediately follows the PS2 game. The Hellgast are thinning out, but they still occupy some areas and the new general is taking hostages, so it's your job to restore balance. It's interesting to see Killzone move from a first-person shooter to a third-person action game, but Liberation boasts the same distinctive art style, and is graphically impressive for a PSP game. There are lots of nice effects, such as enemies that fall into water when you kill them, and even at this stage the game suffered no slowdown. In North America, the game will be released in October, with Europe to follow in November.