Moving and targeting will be familiar to anyone who's played first-person shooters on a console - the left analogue stick moves you back, forth and sideways, while the right stick aims and turns. Targeting, even with the lack of fine aiming that comes with analogue stick controls, is never a problem. For distant enemy, most weapons do have a sharp shooter mode that, with a click of right stick, zoom in slightly. Inadvertently clicking this does happen when you're frantically looking for a pack of crab-like Leapers, which swarm over walls or burst from pods.
Leaper
Ageing Granddaddies whose reflexes are a bit slow, might find a Leaper or a Menial Hybrid attached to your face. When this happens you can unleash the fantastically immersive use of the Sixaxis' tilt controls - namely shaking it like crazy to shrug them off. Given that you can just press the [Triangle] to strike them with the butt of your weapon, it smacks of little more than an afterthought.
Of course, the best approach would be to steer well clear of intimate contact. To do this, you're initially armed with carbine rifle and grenade launcher. Later you're introduced to a wonderful assortment of more powerful weapons; Sniper rifles, shotguns, rocket launchers and Chimeran energy weapons are part of your projectile inventory, with frag grenades, hedgehog mines and gas grenades for the less direct approach. The Chimeran Auger rifle is particularly useful, as its rounds can penetrate objects. Its reticule will identify targets through walls, making it a good strategic weapon. Like all other guns, it comes with a secondary firing mode, in this case setting up an energy shield.
Stalker
When the going gets tough, the tough get mobile artillery - namely tanks, Jeeps and Chimeran Stalkers. The tanks are a bit cumbersome, best used in long-range engagements. Heading through Cheddar Gorge you're introduced to the Jeep which, though technically not a weapon, is damn good for mowing down foot soldiers. Taking command of a enemy Stalker, a spider-like contraption armed with cannon and rocket-propelled mortars, is the most fun.
Though the vehicles all add variation to the game, they're often short-lived segments that seem little more than sub-games. In fact, only on two occasions does their involvement feel essential - using a Stalker to take down a boss-like Goliath and using the Jeep to get through the lengthy Gorge level. Even the Jeep, while fun to drive, is watered down by the inability to take control of the mounted machine gun, which is firmly the domain of the non-player comrade.
To stand a chance of survival you have to learn the different types of enemy creature. More than that, you have to figure out their weaknesses and the weapons that deliver the most damage. Throughout the cut-scenes and in the various pieces of intel you can collect you're introduced to several larger beasts - Goliaths, Carriers, Widowmakers and Angels - but you rarely encounter them during play. In fact, you engage with several Angels, pitched as the big bosses, but only one Goliath. There's also a creature that exists only in notes and radio chatter - The Cloven appear to be something between human and Chimera, but you never find out what they are. When you've wrapped up the campaign, you definitely feel as though you've missed something.