Despite a been-there-done-that storyline, the action R:R brings to the PSP is quite fun.
The game-play consists mainly of getting from point A to point B through a few waves of enemies, flipping a switch, then moving on. Usually the action stays exciting, but the formula does get a little dry by the end. They attempt to mix things up with a couple of cover missions where you need to protect someone for a set period of time, and the odd vehicle mission where you move into first person mode while piloting a mech down trenches.
When you find yourself on your feet, it won't be too long before you have a nice collection of weapons in your arsenal. There's eight slots in your inventory, each for a different weapon with two of the guns you obtain having an upgraded version available by the end. These weapons include automatic rifles, energy weapons, a rocket launcher, grenades, a sniper rifle, and a shot gun. There's an secondary action button as well allowing you to do things like charge up a shot on one of the rifles, activate a shield on another, or change targets for a rocket mid-flight. The weapons also lock on automatically, with the option to zoom or close in for tighter shots with manual aiming. The lock on system works well most of the time, but there is the occasional desire to stay locked on to the guy 100 feet way hiding behind a rock, and not the one charging down on you guns blazing.
There's a great balance between the weapons as well. Each gun has it's own situation where it works best and it was very welcome to see that they all retain their usefulness throughout the entire game. There are apparently new weapons you can unlock by collecting hidden intel and achieving skill points, but I did not manage to reach 100% of these extra tasks on my first time through to see what they are. When your standard armament is not enough, you'll find a few areas where you'll man a larger stationary gun while an onslaught of enemies come charging at you. A pretty standard practice in games like this, but fun nonetheless.
There is a decent variety of enemy types ranging in size, threat level, weaknesses and attack types. You're exposed to many of the baddies you'll face before the game is half over, but thanks to the selection to pick from they don't often get boring to take out. They of course left a few surprises towards the end of the game as well. The bosses and mini-bosses in particular are also plentiful, and you'll find yourself taking down quite a few large foes.
Another item of decent size is the single player campaign. There are 6 missions each with 4 stages, and will probably take about 6 hours to get through on your first run. The check points are forgiving in each of the stages, although by the last mission some of the save points felt a little far apart.
The control scheme was something new for me. This was the first game I've played using the X, O, Square, and Triangle buttons in lieu of a right analog stick. These buttons served to turned you left and right, and look up and down. Even though it was different, it didn't take me too long to get used to and the controls as a whole functioned rather well. The only thing that kept tripping me up was trying to quickly select the right weapon in the middle of a fire fight.
There are some challenging areas that come around where you'll have to perfect your approach, but I was never left with a feeling of hopelessness.
The biggest area of improvement in my eyes would be around the standard sci-fi story-line and the unneeded "M-ness" added to the game. You play as an exceptional solider who, through a certain life changing situation, acted in a way which got him sent to prison awaiting execution. He's eventually pardoned under the condition that he jumps back into the fight via a suicide mission, and ends up becoming the hero we all knew he could be to defeat the alien invaders who are using our bodies for their own means. It's like Rambo meets the Invasion of the Body Snatchers; pretty typical stuff delivered with some eye-rolling dialogue.
Then they have to make sure to throw in course language at least once in any given scene, whether it fits or not, and at one point suggest a sexual encounter that makes little sense to include. They gotta earn that M rating I guess. It's silly really; just let me play the game. And thankfully all of this happens outside of the actual game-play so it in no way impacts the fun of it all.
On paper it seems like a by-the-book take on the 3rd Person Shooter genre, and even so the development team executed it very well making it an enjoyable title. Steady action with bursts of intensity will keep you entertained, and the option to go back and replay sections to get 100% completion will provide some replay value.