The voice of Gearbox’s founder Randy Pitchford cuts through the air: “These players were coming up to the crest of a hill and this wall of flame shot up. Some dude emerged and had an Alien-style flamethrower under his arm, and I was like: ‘What the f**k’s that?’”

Even the creator of Borderlands still gets surprised, shocked, and stands slack-jawed at what’s going on in his own game – when that happens you know you’re in for a treat. The gimmick here is that the bespoke software created for the game generates the weapons randomly. There are over a million variants on shotguns, machine-guns, flamethrowers, pistols, grenade launchers and every other stock death-dealer you’d expect. So many, even Pitchford still struggles to predict what the game will throw-up next.

It’s one of Borderland’s key strengths: the ability to surprise on every turn. Our play of the near-finished code was testament to the game’s ability to dumbfound. We began near the start: our character had been set up using the in-game ‘gene generator’, which had echoes of Fallout 3 about its connection to the game world. Even the simple task of creating a character’s name, class and look is rooted in the game’s universe.

Our tutorial began by following a small robot called Claptrap (terrible name), who soon becomes established as the game’s touchstone for advice, missions and fluff about the alien world of Pandora. A few shootouts later in the town of Fyrestone, and we’d rescued a Dr. Zed, repaired a Med Vender and shot our fill of Skags – a cross between attack dogs and giant beetles. They like human blood.

There’s a nod to Fallout 3 that can’t be avoided, and there’s a sly wink to BioShock too. The game’s world is open to an extent (central hubs are linked by new hubs loaded in as you enter caves and canyons) and detail is rich and constant. Whether it’s the vending machines that dispense ammo, weapons, health, upgrades and combat items – or the eccentric Wild West-style characters, everything helps create a sense of place not felt since BioShock’s watery wastes.

Thankfully the action is masterfully brutal and holds the whole game together. It’s something Pitchford is making every effort to express: “We started with a first-person shooter and came to it with RPG elements, not the other way around,” he explains excitedly. “We took the ideas of growth and choice that define RPGs and added them to the FPS genre, so while a normal FPS would give you one type of shotgun, we give you all the shotguns; one may be short with a wider shot, another is longer for more accuracy, one has two barrels; another has four…” You get the general idea.

That choice doesn’t affect the game’s balancing or gunplay - every weapon, no matter what the game randomly offers you when dropped by a defeated enemy, handles beautifully. The early weapons - an old rusty automatic rifle and a pistol - crackled wonderfully with each pull of the trigger. The old rifle spat bullets chaotically while the pistol was more accurate with softer sounding shots. Every time a bullet hit home the enemy squealed and looked for cover as their lives drifted skywards in little numbers… 8, 12, 11, 14, dead. Borderlands is a shooter, but it’s also an RPG.

The better your accuracy, the greater the damage, with every enemy having weaknesses. For example, the Skags are best shot as they leap at you with their jaws open, exposing the soft flesh of their mouths, and later on, larger Starship Troopers-esque, pincer-wheeling monsters appear with a soft spot on their backs. Hit these to ignite the phrase ‘CRITICAL HIT’ across the screen.