Continuity mistake: Scott and Ian get in the ring to carry Frank away. Dean is holding the second ring up with his right arm, which becomes the left at the cut. (01:27:30)
Continuity mistake: Soon in the Ian vs Ivan fight the two end up on the ground exchanging kicks. Kelly is at ringside; her hair is in a different position on the lapel of her jacket between shots. (01:28:45)
Continuity mistake: Ian and Ivan start trading blows with the referee looking at them kinda frightened in the corner, both arms over the top rope. Next shot and he's watching the same exchange but with his hands down. (01:28:55)
Continuity mistake: For the final part of Ian and Ivan's first round, the timer jumps from 1:03 to 0:58 during one of Ian's punches. (01:29:35)
Continuity mistake: Ivan in his rage puts Ian through the ropes flipping him; to be flipped, Ron Pohnel is holding the ropes; the second one in the first shot, the top rope in the second shot. (01:32:55)
Continuity mistake: Van Damme rips his shirt off and drops the gloves. Starts circling his young opponent. You can see the items he drops but a couple of shots later they are in the corner in different position, which will change again when he brutalizes the opponent against the ropes. (01:34:00)
Continuity mistake: When Van Damme flies out of the ring (handspringing like a pro-wrestler), the surprise and cheer from Ian's cornerpeople is different across the two shots (for instance, Dean leans in to look at two very different times). (01:35:40)
Continuity mistake: In the tournament at the end of the movie, when Dean and Ivan meet in the center of the ring before the match, we can see that Ivan's stance has his back to our view. However, when the shot sweeps over the crowd and judges, and then back to Dean and Ivan, we can see that Ivan is now facing us.
Continuity mistake: When Scott bullies RJ outside the burger place, Scott is in one side of the table and is kicked by RJ in the stomach, RJ falls to the floor and in the next shot Scott is now beside him.
Continuity mistake: When Jason and RJ are putting the wood horse on the floor and drinking the coke Jason's legs change position between shots.
Continuity mistake: After Kelly's party Jason gets to his home and his dad yells him about fighting then gets to the garage and drops just some magazines and rips out the Bruce lee's poster but in the open view you can see several things on the floor.
Continuity mistake: When Scott is using the hose he is sitting on a chair with his house in the background. In the next shot the house is gone and there are some trees. The his dad yells at him and the house is back again.
Suggested correction: You probably hadn't a chance to rewatch carefully. The camera angle changed more or less from Dad's perspective a bit raised, and so you don't see the house but the lawn. All the green in those shots is not trees but rather the lawn, with the same shadows (more or less, the light does not quite match but it's very minor) you see previously.
