From what we saw, it's a pure run-and-gun, keep-tapping-that-kill-button affair. There were some focused moments, such as ambushes, COBRA helicopters to shoot down and a segment that had the two players zapping bad guys by firing blasts from a satellite. There will also be vehicles to pilot, although we didn't see that aspect of gameplay. If you're playing the Wii version, waggling the Wiimote will perform melee attacks and holding it aloft will activate the Accelerator Suits. (More on those coming up.)
From what we were told, there are three character classes: agile guys like Snake Eyes, all-around soldiers like Duke and heavies like ... Heavy Duty. (We're not sure where Shipwreck falls, but we're told his parrot drops grenades on enemies as his special attack.) There are also Joes that aren't in the movie, COBRA regulars that aren't in the movie and classic vehicles -- such as the COBRA H.I.S.S. tank -- that aren't, as you've no doubt guessed, in the movie. (Seriously, the H.I.S.S. isn't in the movie?)
So, what else does a Joe fan have to know? Ah, you'll be able to play as COBRA characters. There are four unlockable characters planned. We can confirm that Storm Shadow is one. Serpentor sadly isn't. In possibly the most interesting bit of info we got out of the demo, there will be unique voice-over when one Joe and one COBRA character team up. For instance, when the Joe shouts "Yo, Joe!" before activating the Accelerator Suits (something new from the film which make the characters faster, stronger and more generic) his COBRA compatriot will start to say it, then bust out an anti-Joe riff.
By now you've no doubt gotten the idea: the game is really simple, likely over-priced, but made with fans in mind. Heck, there's even a chance that references to pork chop sandwiches and body massages from the hilarious "Knowing is Half the Battle" PSA re-dubs will make it in. But will this sort of stuff be enough to make up for the cost-to-experience ratio? We wish we could say, "Go Joe," be we fear it's more like, "Oh, no, Joe."