This is awesome! When I get my laptop and buy this game I will do my best to make some crazy mods! (Some things I plan may not be possible as of yet like throwing a granade that shoots (3) 3 round bursts while mid air if I decide to make a future themed mod for example and being able to change the soldier animations gives me some ideas)
Also is it possible to make tunnels or interiors of buildings at the moment?

<--Pumped
I think it isn't. They have decided not to have interiors if I remember correctly.