Yellow is the opposite of purple, red is the opposite of green... technically, for chromatic accuracy, Horsphoeus should be blue, but that wouldn't be as cool. I vast improvement on the last version (spiky goodness!) But those liftarms on his shoulders are begging to have massive missile launchers attached to them :L
For something so last minute I think you did really well. I really like the legs and the forearms. Though, and you might find this slightly ironic that I'M saying this, but purple is the opposite of green not orange. Mine probably would have been purple if I had more than 3 pieces in purple.