Not your fault but if you buy a DVD you get previews from other movies
Overall its a good story.
At start the movie shows soldiers shooting in every direction and a lot of chaos, men running back and forth without any use.
Somehow I think directors have to get rid of that idea that action means, running around like frightened ADHD rabbits.
The actor who played the South Korean commander did a good job, his character is that of the leader against his will, and he plays it very well.
The movie shows his problems with gaining trust of his men, but gradually you see the students follow.
Specially the trouble he had with the 3 criminals is very well detailed.l
The action scenes are getting better during the movie with the opening North Korean attack on the school as best example.
The students waiting untill the mines and grenades explode.
Worth your money!!