The movie was shot during the summer months and kids enrolled in summer classes were extras on the film. Free Papa John's pizza was served to anyone who would stay after school.
When Shale throws the fourth kid from the window in the library scene his shirt is unbuttoned and you can see that he is not wearing his bullet-proof vest. In the next shot he is taking the vest off.
When Matt starts confessing to Shane after getting hit in the head with his own helmet, his face is clean minus a few scrapes by his left eye but it in the next shot he's sweating and has blood coming out of his nose and mouth.
When the mercs are at the firing range, there are several shots of Shale with people behind him "shooting" a Glock. If you take notice, you can see they are simply imitating the recoil by slowly flipping the gun back.
What are the differences between the British BBFC 18 Version and the Uncensored Version?
A
This decent high school actioner was shown in British cinemas in a version that was shortened by 25 seconds. The following VHS versions contain the same cuts. All the scenes with the, at that time prohibited, throwing stars had to be removed to get an approval from the BBFC. An uncut version has not yet been released there. A detailed comparison between both versions with pictures can be found here.