So Mark Ruffalo was recasted as Hulk after this movie. Edward Norton was originally Hulk, but he had different ideas on where he wanted to take Hulk. Don't worry, you watched the right movie π Can't wait for Iron Man 2!
And a couple of things you maybe missed, or lack thereof. When Mr. Blues head morphed and he smiled, he had an open wound in his head that Bruce's blood leaked into from the broken vial above. So his blood entered his brain, and it teases him becoming the villain known as The Leader. (This is only a reference to the comics, they haven't brought this back up ever since that moment, no spoilers)
I personally love Tim Roths' Emil Blonsky here. So he was injected (twice in this movie) with a blue serum that General Ross mentioned they had kept on ice but was very promising. So he was enhanced. Super strength, speed and agility (they didn't show it all that much, only during the attack at the University did they show him running much faster than the other soldiers, flipping around and giving Hulk some grief) Then he forced Mr. Blue to give him the Gamma radiation from Bruce's blood, basically the same thing that made Bruce into Hulk. So Abomination is actually much stronger than Hulk is, which is why he had a hard time defeating him in the final fight. But overall I do enjoy the movie quite a bit.