Apparently, 17 million weapons just aren't enough.

I repeat, that's 17,000,000 guns, grenades, rocket launchers and other items built for death and destruction.

So, how many weapons will Borderlands 2 -- the follow-up to the surprise 2009 role-playing shooter -- host for trigger-happy video game players? One billion? A gajillion?

Studio Gearbox Software doesn't say, but it's safe to assume players won't run out of options for causing mayhem.

Earlier this week, I revisited the world of Pandora through a demo of Borderlands 2. Based on one of the game's missions, the sequel appears as entertaining and as explosive as the original.

If this is your first trip through Borderlands, here's a quick recap: The original followed four mercenaries traveling to the world of Pandora to find a legendary alien vault.

Fast-forward to Borderlands 2 and its four new treasure hunters, now tasked with saving Pandora from the Hyperion Corporation and its CEO, Handsome Jack.

Two of the characters were on display for this demo: Maya, the Siren and Salvador, the Gunzerker. As with the first Borderlands, characters specialize in certain attack tactics and boast a special power for use during combat. Maya can phaselock enemies, freezing them in place for teammates to blast away. Salvador can go "gunzerking," which lets him wield a second weapon and rip apart waves of enemies.

As players kill enemies and finish missions, they can "level up" by earning experience points and unlock perks that boost their health, combat prowess and special abilities. So, in the case of Salvador, his "gunzerking" skill can last longer, deal more damage and even generate ammo.

Playing as Salvador, my first quest was to assist Mordecai, the sniper featured in the first Borderlands. His trusty pet Bloodwing has been locked up and players must rescue him.

Right away, it's clear Gearbox wants the game's plot to play a stronger role. Characters players seek out for missions stand right in front of them, not represented by a card with text like the first Borderlands. Developers have also eliminated the process of backtracking to check off a completed mission, allowing players to fully immerse themselves in a task without interruption.

There's a healthy selection of enemies for players to test out their robust arsenal, some new and some with fresh powers. The Skags -- four-legged wolf-like creatures -- are back, in all their sizes and flavors. Some chase you down engulfed in fire, while others spew acid. A new variety of Skag can empower smaller counterparts, such as the giant shock Skag that turns pups into gnarly little forces of electricity.

Players will also encounter Stalkers, winged reptiles that can turn invisible, and robots fighting for Hyperion. They remind me of twisted Transformers, morphing into bulldozer-style attack machines or spinning fast propellers to deflect gunfire.

Of course, they're no match for the Borderlands 2 arsenal, the game's main attraction. Weapons are scattered everywhere, hidden in giant chests or even piles of Skag vomit (yum!).

The highlight of the Borderlands 2 demo popped up about halfway through, as myself and a Gearbox rep battled through an army of Hyperion robots, including one that shot lasers and generated all-around havoc.

Or so I'm told. There's a shotgun in the game made by fictional weapons maker Jakobs. It only fires two shots at a time, but has a scope and great range. While my teammate, playing as Maya, took on the robots head-on, I flanked left down an embankment near a bridge.

After roughly 15 seconds and about 7-8 shots, that robot armada was wiped out, including the one that supposedly fired lasers.

As for the "gunzerking" ability, imagine becoming Tony Montana from Scarface, when he introduces "his little friend." You feel drunk with power, as Salvador whips out two guns and mows down enemies in a flurry of gunfire. It's easy to forget you can actually get killed during this sequence as you run around like a madman shooting every opponent in sight.

Whether Borderlands 2 has 17 million weapons or 17 trillion, the role-playing shooter feels as exhilarating as its predecessor, judging from the demo. The world is vibrant, the weapons still feel comfortable to handle and the foes are ferocious.

Borderlands 2 launches on Sept. 18 for PC, PlayStation 3 and Xbox 360.