When Dwayne Johnson ('The Rock') was attached to star, this film was known as The Rock Movie. When he left to work on The Mummy Returns (2001), it was listed for a short while as Untitled Sci-Fi Project, and when Jet Li came aboard, it became The One.
At the end, when Gabe Law is in his new universe, he sees a dog, that has been hit by a car, lying on it's right side on the street. When he picks up the dog, it's right front paw is bent back, hinting that it is injured. When Gabe brings the dog into the vet clinic, it's right front leg is straight and Gabe seems to place the standing dog on the counter top.
In the first chase where the police of the Anubis Universe are chasing Yulaw, the first car goes under the partly raised garage door and hits its lights on it. The siren dies and the light and siren get broken off. When the car drives on, however, the top is sparking but the lights and siren are intact.