Continuity mistake: Merek's bird is sitting on his shoulder facing backward. In the very next shot, as he stands, the bird is suddenly facing forward. When he starts to sit down, the bird is still forward, but in the next shot, a close-up of him sitting, birdie is facing to the rear again.
Continuity mistake: Mark injects April with plain water, telling her to play dead. She shouldn't have to play. Water in the blood stream can create oxygen bubbles, which can be lethal in a matter of minutes. He should have used saline or glucose instead. Those solutions have been de-oxygenated and purified to prevent giving patients the potentially lethal "bends."
Continuity mistake: Mark, April and the professor leap from a boat seconds before a bomb goes off aboard. But in the shot of the boat exploding right after they jump, there's no one in the perfectly calm water, and the empty rubber raft is still alongside the burning boat. Somehow, though, the escapees are rowing to safety in that same raft a few shots later.
Revealing mistake: The climactic chase occurs in an amusement park, supposedly in Brighton, England. But several things give away the real filming location, among them an ad for 15c (not 15p) snow cones, two very American-style phone booths, and best of all, a pole proudly sporting both a U.S. flag and a California state flag, visible in the background behind the phone booths.