If you've played
Killzone 2 or
Killzone 3, you might be utterly gobsmacked at just how faithfully the experience has been replicated. The game is easily one of the best-looking portable titles I've seen; while it may not be quite up there with its console brethren, it comes incredibly close.
As far as gameplay goes, it's classic Killzone, with the twist that you're killing for money. Much like in Bulletstorm, kills earn you currency which can be used for upgrades and better gear. Movement is largely kept the same, though sprinting is handled differently due to the Vita's lack of clickable analog sticks. However, for a somewhat twitchy shooter, it feels great. Naturally, the tactile pleasure of having a controller in your hand is no substitute, but the action mostly works. There are some touchscreen inputs involved with melee attacks; I've never been a fan of that kind of stuff, and hope that developer Guerrilla Cambridge keeps the gimmicks to a minimum.