As for the new guys, Robin's just a Batman-wannabe in a gaudy costume that gives me a headache to look at, but Atomic Joker wins bonus points for being a head in a jar.
In gameplay Nightmare Robin's a fast assassin type, who can disrupt enemy healing and chain together lighting-quick strikes. He's also got a teleport and a blood draining final move called 'Feed the Beast'. Oh yeah, he's part vampire. Should have mentioned that.
For an actual head in a jar strapped to a brutish minion on a unicycle, Atomic Joker's quite handy in a fight. As you'd expect his attacks are fairly ludicrous, and include a 'Hot Potato' bomb that bounces across to multiple enemies and a banana peel move that knocks enemies over.
The new tutorial mode has several famous DC heroes teach the player a few tricks. It unlocks six heroes for free upon completion, giving newbies a bit of a kick-start into the game.
Infinite Crisis is in open Beta right now. You can download it for free over on the .