We so down for some co-op action - Tradução em português

hey folk, i'm having some problems trying to figure it out, what does it mean "i'm so down"
i was watching this podcast called Co-op and this is the intro song
i really would appreciate some help

the thing i like about you most is
you run away with me
so pack your pants and your shotgun too
we might run into zombies
we always down for that co-op multiplayer action
we always down
we're so down, we're so down, we are so down for co-op
we are so down for that co-op action

it's the first time i'm using this forum, so if i did something wrong just tell me, no hard felling
see you