What I Loved
This is a warning to bullies everywhere!
Everybody can relate to dodgeball getting out of hand. It rewards athletes for their quickness, and for being ruthless bullies.
In this particular case, the bully and the coach have backed the protagonist against the wall, and he must take decisive action. I liked the fact the protagonist stole from his stepdad (who's also a bully) to exact his revenge on both of them.
What I'd Love To See
Would like to see the protagonist NOT reveal to his stepfather that he killed his son. The "I don't have a brother" tells is a sure way for the protagonist to get killed. I don't think coach would let it slide if he knew his stepson killed his stepbrother.
The conventions of screenwriting such as POV and SUPERIMPOSE have not been followed.
I would also like to see the active voice being used. It's not difficult to do and makes for a more exciting read.
All in all, a great story!