For the first time in the series, Gas Powered Games - the developers originally affiliated with the Dungeon Siege franchise - have dropped the reigns while boss Chris Taylor takes on a slightly more laid-back role, overseeing Obsidian's development of Dungeon Siege III. Yeah, that Obsidian, the one whose hand has historically been stuck firmly in the cookie jar of Knights of the Old Republic 2 and Neverwinter Nights 2, and who recently put out the rather excellent Fallout: New Vegas.

Obsidian's "choice and consequence" mantra, even its history of turning out thick story-centric RPGs, might seem at odds with Dungeon Siege's own tendency to lean toward a pick-up-and-play direction. But the result is a lovechild of both genre variants. Dungeon Siege III is a combination of the combat-centric role-players of old, and the kind of intimate involvement with story that has been adopted by modern Western RPGs; a worthy stop-gap between now and the upcoming Diablo III.

This is where you are in the story so far: via the means of what looks like an impressive load of concept art, you're given a history lesson on the state of the Kingdom of Ehb. The powerful factions that have held Ehb together have fallen; as one of the few remaining members of the 10th Legion, the protectors of the land, it's up to you to rebuild the once great clan and stop Ehb from falling into darkness. On your side are unique companions who join you as you progress through the game.

So while Dungeon Siege III is busy consuming every featured RPG trope of the last two decades, you'll either spend your time finding this derivative or reassuringly traditional. To a degree even this adopt-what-works technique is standard for the genre. Most newfangled role-playing titles have a tendency to distil what has clicked for the genre and throw those features together in a patchwork style. In this game you'll quickly be introduced to quest-givers' yellow exclamation marks, as popularised by World of Warcraft. You'll have city hubs chock-full of NPCs to take quests from, and you'll have branching dialogue trees when dealing with those NPCs. Incorporated into the game is a useful albeit finicky breadcrumb trail, which is helpful considering the size of the world.

In my recent hands-on I played as Lucas, the lead character of the Guardian class of melee fighters, from the halfway viewpoint between a conventional Diablo-like isometric perspective and a third-person action-game camera. The Guardian has a few special abilities available to him, which include being able to switch between one and two-handed stances. One-handed gives you more leeway to deal heavy one-on-one damage with your sword, whereas two-handed allows you to deal with bigger mobs of enemies.

A Guardian starts off with Shield Pummel, a one-handed ability that bashes enemies with a three-second stun. But Dungeon Siege III is more a game about continuously changing your stance than it is about sticking with the one trick that works, so after a level-up you can go for a mob-focused ability that lets you slice through tens of enemies at once, leaving you with only a few stragglers from the outskirts of the group to take on in your one-handed stance. Level up again and you'll be able to get Graceful Repose, a health-based ability that regenerates 5 per cent of your life over 30 seconds. Along with abilities you have a talent tree, giving you more general enhancements.

Oddly the game doesn't include some of the more standard practices of the genre. Dead enemies drop orbs, but in order to pick them up you have to take part in a multi-step process of walking over to them and clicking near each independent orb. There's a similar level of tedium when looting treasure: One click to open a chest and watch as treasure spills out around it; another few clicks to stand over each piece of trinket and then add it to your inventory.

Despite the sometimes odd, occasionally too-conventional slant, Dungeon Siege III looks surprisingly good, even at a pre-alpha stage. Instead of throwing new content at the game's existing framework, Obsidian has re-built the game from the ground-up using its own engine - Onyx, for those of you keeping score at home. So even with the bulk of the demo being spent exploring your standard, everyday role-playing environments - caves, woods on the outskirt of medieval villages, and various rooms in castles - there's a level of gloss thrown on that makes what would otherwise be derivative areas look anything but anachronistic in this day and age. Dungeon Siege III might be generic but so far it looks like it's wearing that generic sash well.

Dungeon Siege III is due for release on PC, PS3 and Xbox 360 in 2011.