Continuity mistake: When General Ross reappears at the end, he is standing directly behind Gabe Jones. A couple of shots later, he is now several feet to Gabe's left. (00:20:22)
Continuity mistake: When Betty and Gabe Jones are talking in the end, there is a brick wall in the immediate background. A few shots later when Betty greets her father, the wall is nowhere to be seen and the room is considerably deeper. (00:20:15)
Continuity mistake: When Gabe Jones is requesting backup, in the wide shot, his brown hair is more golden in color. (00:14:45)
Deliberate mistake: The footage of sharks swimming past the base windows in pairs is immediately recycled twice. (00:09:34)
Continuity mistake: When Bruce is rappelling down the shaft, at one point he turns his body face down, and you can tell by the rate at which the background is passing by that he is instantly going slower than the previous shot. If anything, his speed should have increased since he's no longer in a position to slow his descent by using his hands to rub against the rope.
Other mistake: When Betty is going over the plans to infiltrate Sea-Base, she mentions they have to go ten floors down. When we see the base, it is nowhere near tall enough to be ten floors.
Factual error: When Bruce is tying the rope through the handles of the magnetic devices to prevent falling onto the laser beams, he only loops the rope through the one on the left, he doesn't tie a knot. The moment he started hanging onto the rope, his weight should have pulled it through the handle.
Answer: The Hulk is a giant brute who smashes everything in his path when he is angry. In Ang Lee's "Hulk," General Ross, played by Sam Elliot, explains it to his daughter.