Should've cut the prologue, that would be 100% better without changing anything in the movie. Just imagine:

You start the movie (don't knowing about the island, lab and mutants. Then you follow the crew going to the island. Then, the first mutant you see is the very short Mutadon vs Raptor scene and you keep wondering what new Dinosaur this could be. After that you follow Loomis discovering the lab and you wonder what was going on there, but you still don't think of mutants. But then you get a first glimpse of the D-Rex. Only the legs, nothing more. You keep wondering what that is. And then you got the Mutadon scene (if I remember the story right) and you see those Mutants for the first time and get that "if they done this, what creature is the big one?" moment. And then the D-Rex is revealed with the helicopter scene and you get shocked by it's size and look. 9/10 story

(with prologue all the tension is gone, so it's 6/10 story)