Ken Kensei's character is credited at the end of the film as "Master Welling". In the film, he is "Master Takeida".
During the main fight between Gary Daniels and Darren Shahlavi, wires can be seen while they make the high jumps.
Despite being a boxing champion, Eddie Cunningham doesn't use a single boxing technique. He's obviously a kickboxer restricting himself to hand strikes.
A safety harness is visible, attached to actor Gary Daniels when climbing up the steel wall.
When the character of Darren Shahlavi defeats Hakim Alston and lifts him over his head, the wire and pulley holding Alston aloft is clearly visible in the upper right part of the screen.
Obvious stunt double in a wig when Dutch (Rob Van Dam) is thrown through the window.
Dutch is said to be "Toughman" champion, but he doesn't fight like an amateur boxer which is what the Toughman contest is.