Near the beginning of the film, when Ed tells Jesse not to raise the lever that opens the shaft with the 150-foot drop, the lever is already up when Ed first points to it. Then we cut away, and when we return to it, the lever is down and Ed flips it up.
During the fight between T-Rex and the forklift at the end, there is a small red truck in the background, which is clearly a cardboard cut out, indicating that it's a miniature set.
The military chopper has the same logo that Reed and his crew have on their uniforms.
When McQuade intercepts Ben and Monk as they are about to take the stairs down tot the restricted sub level, three pieces of tape (different colors) are visible on the floor for marking the actors positions
When the T-Rex chases Reed and Jesse into the elevator, as the doors start to close, the head of a crew member is visible at the bottom of the screen pushing the dolly on which the robot T-rex is mounted.
Two crew members are visible at the bottom of the screen when the camera cranes up for a master's shot of the restricted sub-level (before they discover the tooth).
When the raptor is pulling Rawlin's arm off, the puppeteers's brown shoe is visible at the bottom right corner of the screen (full screen version).
Dips down into frame above Reed's head before Jesse sits down at the computer (this is the scene where they discover where to get dynamite).