Mine wouldn't move at all, then there was a pop and it moved just like the IM2 head.
Here's some pictures comparing the two. Sorry they are just iPhone, it's all I've got.
Left:IM2
Right:Avengers
The feet also are a bit dirtier on this one and it looks like the gold color is slightly darker on the avengers version and the Tony Stark head is more tan.
So what's the deal is it the same figure with just a different paint job?