Guns aren't just found on your enemies and hidden in caves, either, but can be located in randomised RPG-style "drops". The local wildlife enjoys munching down on the odd bandit, and what's left behind often yields bonuses, as do treasure chests with random contents - grenades and ammo, yes, but also guns.
The experience itself varies, too, thanks to Diablo-ish randomisation of combat within specific levels, which might as well be instances. We're shown the Iridium Mines level, which splits the two players up on different paths. The bandits inside are holding hostage an alien artifact, which is a valuable commodity on Pandora, and the administrator of the nearby Newhaven Settlement wants you to get it back. The quest's the same across game sessions, but what happens isn't: in our case, the two players converge on a bunch of bandits sat around a campfire roasting a dog-like "skag", and while one player distracts them with a sniper rifle the other assaults from the flank and cleans them out.
Combat itself is bloody as well as dynamic. Gearbox has no problem getting an "R" rating, so there's dismemberment galore - flying heads, twitching legs - and lots of gibs from cluster grenade chain explosions. On the defensive side, players have a recharging, Halo-style shield and can pick up things like orb shields to augment that. Your ally's health is shown in the top-left, too, so you can keep an eye.
Outside the mines, we're promised Pandora is vast, taking hours to traverse. Vehicular transport and combat will play a big role to assist. Inevitably one player drives and the other rides shotgun, but you can switch places at any time without stopping, and the things you do in the vehicle also contribute experience points. You'll also be able to customise your ride with different weapons and other add-ons.
That's all we're shown for now, but it leaves a decent impression. The incursion of MMO and RPG ideas into FPS thinking is nothing new (Rage and Fallout 3 may be new examples, but Deus Ex can stick its hand up among others), but the promise of procedurally generated weapons and persistent characters across online co-op games (which will support four players total) is shinier, and we enjoyed the blue-tinted mines with their shantytowns and Ewok bridges, strewn with body parts.
And whereas other developers contributing to the new wave of RPG-influenced shooters run the risk of scooching too close to the cape-and-armour-clad inventory clerk side of things, Gearbox's background is in shooters - the excellent Brothers in Arms, most notably - and Borderlands is a shooter first and foremost. "What we're trying to do is add a persistent character to a shooter experience," Gearbox president Randy Pitchford said recently. That works best for us. Look out for more closer to the game's release next year.
Borderlands is due out on PS3, 360 and PC in 2009.