I really don’t understand the rules of it but hopefully I would get amazing advice!
There are several multiplayer levels; which one are you confused about? Zero Sum can be played by anyone and is in a tournament right now: http://codecombat.com/play/ladder/zero-sum – it should explain itself okay in the guide, but you do need to know a bunch of the programming concepts CodeCombat teaches to do it.
Dueling Grounds is the easiest one to play: http://codecombat.com/play/ladder/dueling-grounds – but it mostly is a playground for testing different gear and heroes you have, since there’s not a lot of strategic depth.
Oooh, GREAT!!! Thanks a lot!!!