Outside of the more tactically minded shooters, "co-op" is fast becoming one of the most abused terms in gaming. Lots of games boast about it but few offer a genuinely co-operative experience. Sticking two players in a gameworld and occasionally asking them to press buttons at the same time to open a door shouldn't really count.
For the latest Ratchet and Clank game, the tenth in the series, Insomniac is hoping to put things right. As the name clumsily suggests, it's a game designed especially for four players.
The concept is that one of Dr Nefarious' latest gadget-fuelled attempts to defeat Ratchet and Clank has gone spectacularly awry, resulting in Nefarious, Ratchet, Clank and hapless cowardly superhero Captain Qwark being snatched up by something called the Creature Collector. In the tradition of everything from The Defiant Ones to Enemy Mine, former enemies must work together to escape a common foe.
The game is playable in a drop-in and drop-out online mode or as a single screen local affair. The switch to co-operative play has meant that the third person viewpoint of old has been swapped for a more overhead camera. It's appropriate, really, since one of the game's many touchstones would appear to be Gauntlet - that early pioneer of four-way action gaming.
Octonok Village is the stage chosen for our demo, taking the quarrelling quartet through a seaside location and culminating in an impressive boss battle against a gigantic octopod creature.
It's a frantic mixture of combat, resource collection and mild puzzle solving that should be instantly accessible to most. There doesn't seem to be any particular advantage in playing as one character over another, so success depends on skill rather than being the first to bagsy the favourites.
Co-operation at its most basic can be found at level checkpoints, where all players have to tag in for the game to proceed, but Insomniac's love of wild weaponry ensures that there's more to it than that.
The weapon wheel will be familiar from previous Ratchet games, but now you have four players unleashing mayhem. Of the weapons available for our short playthrough, each has immediately obvious co-op benefits.
At the more obvious end of the scale is the Warmonger, a beefy rocket launcher with devastating power. More intriguing is the Thundersmack, which creates lightning clouds that automatically start zapping nearby enemies. All weapon use is cumulative, so if everyone starts using the Thundersmack, you can build up an enormous black cloud capable of delivering massive shocks across the screen.
For those who prefer a support role there's the Arclasher, a whip-style gizmo that can be used to pin enemies in place so that your team mates can go to work on them.
One notable example of how these weapons can work in combination comes when you need to power up a generator to open a pathway to the next area. Slug-like Slorgs are slithering around, and can be electrified and then corralled into a receptacle to supply the required power. Grabbing, frying and shoving – when all four players are working to a common goal, it's a truly co-operative experience.
Even with just these three gadgets, the combinations were instantly satisfying and agreeably destructive. But that's not all the technology on offer.
Every character also comes equipped with a Vac-U-4000, handy for slurping up the ammo and nuts-and-bolts currency that predictably spills from smashed scenery items.
The Vac-U-4000 has a more amusing use, though. You can use it to pick up other players and then shoot them into the air. This is vital for getting past certain sections, allowing you to fire friends across otherwise impassable gaps or launching them over the heads of unsuspecting foes for a powered-up slam attack. Getting players in the right position to be vacuumed up took some fiddling, so here's hoping that gets tightened up before release.
Or maybe not. You can also use this Dyson effect to irritate other players, by shooting them off ledges so that you can snaffle the spoils of a big fight. Insomniac has deliberately designed the game so that falls are non-fatal and come with no penalty, but there is a strong competitive streak running through the game to balance out the co-op stuff.
At the end of each stage, everyone is ranked according to their performance. The player who collected the most bolts is lauded, as are any players who excelled in combat. Those who died most or simply didn't pull their weight are gently mocked.
It's just enough to ensure that play strikes a finely tuned and constantly shifting balance between wilful partnership and kudos-driven aggravation that mirrors the heroes-and-villains team up angle of the story.
The final trick up your sleeve is a leash that can connect you to the nearest player. This proves extremely useful if you're getting left behind, allowing you to bungee across the screen to catch up with your mates, or if you mistime a jump and need to pull yourself back to the rest of the pack rather than waste seconds respawning.
But, again, it works in more ways than that. Four-man swing points are common, requiring all the players to form a pendulous conga line and then synchronise their momentum to reach the other side of a large gap. Used in conjunction with the Vac-U-4000 it also means that as long as you can slurp and shoot one player to a distant platform, everyone can join them just by using them as a mobile grapple point.
At every turn in the demo, there's a sense of a developer really exploring the ways players can work together while still maintaining a competitive streak. Every weapon and gadget has multiple uses, and even in this short section of the game it was clear that the levels have been designed to encourage you to try as many of them as you can.
What remains to be seen is how existing Ratchet and Clank fans will take to this new style of play. It's fast and manic, a far cry from the platforming precision of old, and it's sometimes easy to lose track of things in the chaos.
That said, it is enormous fun, in that effortless way that Insomniac has brought to the best of the Ratchet and Clank series, and – if nothing else – promises to be a co-operative game that actually requires co-operation.