If you've ever played a first-person shooter on the PSP, you know that the controls invariably suck, thanks to the lack of a second analog stick for looking around. The creators of Killzone know that too, and that's probably why they made the sequel to their PS2 shooter into a more handheld-friendly, top-down action game. Unlike every other shooter to go through a similar conversion, though, Killzone: Liberation is unique for not only being great on its own, but for actually improving on the console original.
As Capt. Jan Templar, you'll storm through war-torn trenches, mine-filled swamps and futuristic military bases, fighting a mostly solitary war against the Nazi-like Helghast army. What makes Liberation interesting, though, is how many elements it borrows from FPSes, and how well it implements them. You'll need to duck behind cover constantly, manage an extremely limited arsenal (you can carry only one gun at a time, as well as a few grenades) and sometimes order a computer-controlled sidekick around. Terrain also factors in heavily, as high-up snipers can instantly turn your hiding places into deathtraps.
In contrast to the gameplay, the controls - tailored to the PSP - are context-sensitive and simple. Templar targets foes automatically, so long as he's pointed in the right direction, and shooting while behind cover automatically makes him pop up and squeeze off a few shots before ducking down again. Issuing orders is similarly easy, as time slows to a crawl, enabling you pick a pre-designated strategic location or target. It might sound overly simple, but things like this effectively keep Liberation from tripping over its own complexities.
Although the controls are easy, the action is anything but. They might look like stormtroopers and pour out of magical closets in one-to-three-man waves, but the Helghast are a formidable enemy; most of them are smart enough to hide behind cover while fighting you, and the really scary ones carry powerful shotguns and toss grenades to flush you out of hiding. They're also fond of traps, and so you'll constantly have to deal with hard-to-see mines, laser tripwires and impossible-to-hit spider robots that explode when they get close to you (or close to an enemy, which makes them fun).
You've got a few advantages of your own, though; each stage is filled with weapons chests (which pack guns, explosives and health packs), and a quick life boost is usually just a smashable crate away. There are even a few times where you'll get to pilot a big, powerful vehicle, like a tank or a hovercraft, that can smash through the Helghast with satisfying ease. (Of course, these points are usually where the Helghast start carrying missile launchers, so the benefit is negligible.)
In addition to the lengthy campaign mode, Liberation throws in a bunch of unlockable challenge modes - essentially quick, pick-up-and-play skirmishes with simple, pre-defined goals - that can boost Templar's abilities. It also features a slew of multiplayer modes, including a two-player co-op run through the campaign, a six-player deathmatch and team-based capture-the-flag, team deathmatch and assault game modes. These are incredibly fun if you've got six people with PSPs together, but if you're not so lucky, a downloadable patch enabling infrastructure play will be available soon from the game's official site.
While it eventually hits near-unplayable levels of insane difficulty, Killzone: Liberation stays fun enough to keep you playing no matter how frustrated you get. And hey, if you get sick of the campaign, it packs in plenty of other things to distract you. Liberation also scores points for tailoring its entire approach to the PSP, instead of just offering up another crippled retread of an existing console game. That - along with Liberation's grueling, nonstop action and sweet visuals - makes this one of the strongest shooters on Sony's handheld.