The main weapon utilized by the Insomniac developers and producers in our hands-off demonstration was a vacuum gun that could suck in items and blast them out at the baddies. Players can team up by sucking in teammates and firing them at enemies, creating special moves -- like a mortar attack -- in the process.
In another scene in the demo, all the characters plummeted down a wind tunnel and had to hold hands to get lifted back out. Here, Insomniac says that it will "incentivize playing cooperatively." And while not falling to your death is a pretty nice incentive, playing nicely together will also net you co-op points. Insomniac hasn't said what those will be used for, promising to explain it at a later date.
Even with the cooperative incentive, we know there are a couple of jerks out there, or players who may be too young to understand what's going on. To counter that, you'll have the option to shut off the competitive elements of the game, making it a more family-friendly experience. The developers say they don't want to be responsible for tearing people apaht.
Ratchet & Clank: All 4 One features drop-in/drop-out play at any time. There's the option to play offline or online with any combination of players. If you're playing solo, the game will give you a bot, so there will always be at least two characters on screen. Other players can revive a fallen comrade, and if everyone dies they start at a checkpoint.
It'll be interesting to see how many more cooperative elements are added to the game before the end of production. There was no discussion of Move nor 3D support at this time. All 4 One is expected to release in the fall of 2011.