Killzone: Liberation is an angled, overhead shooter from Guerilla Games, and it's their followup to the Killzone, the PS2's purported answer to Halo. With no Halo game to compete with on the PSP, the ambitious team at Guerilla Games turned its sights on showing off the full capabilities of the PSP, and what they came up with is a really good game.
In most missions, you'll be taking cover behind crates and popping out to eliminate enemies. If you get caught up in a run and gun situation, bullets move just slow enough that you'll have a chance to either run and evade them or roll out of the way. Narrowly dodging bullets and popping out from behind cover makes for really fun and satisfying combat. There are occasional vehicle sections too, but they were more frustrating than the on-foot combat. It was difficult to drive and evade bullets with the analog nub while aiming the vehicle's turret at enemies with the L and R triggers. I would end up stopping the vehicle to aim while soaking up damage. Thankfully, being in a vehicle was never necessary, so when my ride inevitably got destroyed, I could return to taking cover behind crates on foot.
Always staying behind cover was incredibly important throughout the game, because one of the most notable things about Killzone: Liberation is its difficulty. On Normal, the game is hard. You really need to take advantage of the given weapons and power-ups, sometimes even doubling back to pick up health packs you didn't use earlier. Even then, there are times when your skill and patience will be put to the test.
While the game does get easier as you unlock more weapons and upgrades through collectibles and mini-games, the see-sawing difficulty makes the it feel unbalanced and frustrating. On Normal, the game starts off hard and then gets even harder in the middle. On the back-end, thanks to weapon upgrades and the enemies not changing up much, the game gets much easier than it was even at the beginning. While the game is fun, the fun comes with a lot of frustration that can be really off-putting.
The game also has some design issues. Occasionally, you'll run into problems with double-tapping the L trigger to perform an evasive roll. It feels like the PSP's physical trigger buttons and the game's relatively slow speed combine to make timing an effective escape unfairly difficult. Mix in bad explosion design
and you'll find yourself dying more than you think you ought to.
The story in Killzone: Liberation has you freeing your friends from captivity and routing out a traitor, but if I wrote more than that, I'd run the danger of out-writing the in-game story's word-count. The story is less than light, serving as barely enough of a reason to march from A to B through the 16 (not including DLC) missions.
With regards to DLC, Killzone: Liberation pushes the capabilities of what the PSP can do. Built into the game, there are options to connect to Killzone.com to unlock rewards and skins online as well as in the game. Additionally, at the time of this writing (two and a half years after the game's initial release), the available DLC adds a new four mission single player chapter to the campaign and an online (infrastructure) mode to the multiplayer.
While all of the content that the DLC and connectivity brings is great, it sometimes makes the game feel like a tech demo. I installed all the updates before playing the game, so I don't know how it would have been different when it was originally released, but if the retail game ended at the end of chapter four the same way the updated version did, the game's already light story wouldn't be a cliff-hanger, it would be flat-out incomplete. It takes the downloadable chapter to bring the story to a close. Additionally, for no apparent reason other than that it can, the game requires connection to Killzone.com for unlocking content on the disc. Both the downloadable chapter and the online unlockables feel designed to show off what the PSP is capable of doing rather than providing a clean, seamless experience.
Including all of the DLC, Killzone: Liberation is a fun, exciting action shooter, and it shows that the team at Guerrilla took the time to craft a unique experience for the PSP. While the game does have some balance and presentation issues, the core game outshines them. Now that the game is cheaply available for download from the Playstation Network store, there's no reason not to play it.