There's a strong argument that the PSP needs more games like Killzone Liberation. It doesn't feel like a forced experience similar to certain titles that seem to flare up on the portable console. The top-down view works perfectly and the game mechanics don't choke when things get hasty on the buttons.
The demo I got my hands on was good at providing a glimpse into the prowling nature of the game. You walk silently and carry heavy hardware, spotting an enemy and dispatching him as needed. They aren't just dummies either. The enemies require more firepower to take out than you would initially expect.
This makes you consider strategy a bit more. Running through with guns blazing won't always do the trick. You'll have to duck behind crates and consider an angle of attack. Because of this, the pace is steady and unwavering, so don't expect a raw shoot-em-up. Liberation is definitely worth checking out for gamers interested in this type of gameplay.