Its going to be way to linear to be Jurassic Park like. The whole thing of Jurassic Park is free form dino's and can come from anywhere at any time. I LOVE that there's a new attempt at Jurassic Park. And massive respect for that, BUT beleive me it will be your biggest downfall if its soooo story based.
Like the very good Ghost Busters game. Only good for 1 or 2 times.
PLEEEEASE maybe take a look at the Grand Theft Auto and Hakuna Matata Games.
They have a great balance of freeform and story. :o