The CG model of the mutated Gilas used in the film is actually a stock Dino Beast model from Turbosquid.
An early synopsis of the film had the monster be a scorpion. For whatever reason, it was changed to a gila monster.
At 55:57 Linda describes the gila's glow as "naked to the visible eye". The English subtitle confirms this nonsense. The line should probably be "invisible to the naked eye".
The train that the Gila monster attacks is a British Rail InterCity 125, despite the film taking place in the United States.