In The Amazing Colossal Man (1957), Glenn's fiancée Carol mentions that he has no existing family members. However, in 'War of the Colossal Beast', Glenn's sister is prominently featured.
Although Glenn is supposed to be 60 feet tall, in the final scene, when he reaches over the Griffith Observatory, he almost touches Joyce. The actual distance between Glenn and Joyce would be at lest several hundred feet.
In The Amazing Colossal Man (1957), army doctors mention that Glenn's heart has not grown proportionally with the rest of his body and that it will literally explode in a matter of days. In 'War of the Colossal Beast', which takes place some time after the previous film, Glenn shows no signs of the existing heart ailment.
Swanson and Murillo find the tracks of the missing truck, but in the next scene the newscaster on the radio says "(The truck) disappeared without leaving any tracks," possibly a misspeak by the actor.
Maj. Baird says the Colorado River, where the Colossal Man fell into at the end of the first movie, is a mile deep in some points. The deepest the river gets is just over 100 feet.
The US Department of Medical Research is considered for taking charge of the colossal man. There is no such department.
Joyce introduces Mexican police Sgt. Murillo as "This is Sergeant Luis of the Mexican State Police". There is no such organization as "Mexican State Police"; each state in Mexico has its own police force, so in the state of Morelos it would be "Morelos State Police", in the state of Guerrero it would be "Guerrero State Police", etc.
When Joyce Manning is on the phone with the "Red Cross People" (45 min.) two shadows are on the wall. One is Joyce, the other to her right (frame left) moves independently of her at the end of the scene. Obviously crew.
Glenn escapes from the Los Angeles Airport and turns up in Griffith Park. This means that a 60 foot disfigured giant moved through some of the most densely populated areas of California, including Los Angeles and Hollywood, without anyone noticing him.
Hal Torey plays the official at the Department of Health and Welfare but is not listed as such in the cast list.