Revealing mistake: When the Hulk walks through the stream, the water doesn't react to his feet. (00:59:20)
Revealing mistake: In the beginning of the film, Bruce Banner's hair is a dark brown and looks natural. When he is doing the anger control exercises, he is obviously wearing a black wig which is not natural looking at all. This happens a few times during the movie - it switches from his natural hair to the very dark wig. And at times, even his eyebrows look much darker and thicker.
Revealing mistake: In the scene where Bruce is in the helicopter hearing about the other "hulk", the camera is the only thing being moved around to simulate a shaky helicopter ride. The equipment nor any of the actors inside the copter are moving around or stabilizing themselves according to how bumpy the camera movements are making it out to be.
Answer: Yes. In the alternate opening, after Bruce turns into the Hulk and causes the ice to collapse, a huge chunk of ice is broken free from the ground. In this ice is a figure dressed in blue holding a round shield with circular red and white stripes. The best way to see this is waiting until the huge ice wall breaks and then slowly advance frame-by-frame and eventually Captain America and his shield will be seen.