I'm actually a bit disappointed now that we aren't going to get a Adam Warlock, Quasar or Firelord. Heck I'd be THRILLED with a Drax in that costume ha. Leaving out Warlock seems like the biggest miss tho considering how crucial he is to the storyline.
But then again the original concept art was only just the beginning. They could easily throw in the other characters later like they added additional X-men proximity pieces. I hope they do!
Oh and here again is the concept art of the other characters. They seem to have done Thanos exactly as you see below in the snippet, so you would think the other characters would be like the concept art. I think everyone pose wise looks great except Cap and Spidey, which is a bit of a let down. Hard telling without the full reveal, but Cap looks like he's crouched over throwing his left arm back. Shield I'm guessing is in right arm blocking. Except that doesn't make sense because what would his left arm in the air be doing? Maybe left arm has shield winding up to be thrown, and right arm is pointing ahead. Spidey looks like he's leap frogging something, which I get makes sense for the character, but just not the pose I would prefer him to be in.
