Flow of sentence structure

I'm having a sort of conversation with another student about sentence structure, this other student is advocating short simple sentences while my tendency is to make them so long they tend to be run on.

I posted a body paragraph of my rough draft, as was the assignment, for critique. He was absolutely correct with one of them but I don't agree with the others. Here they are:

My sentence

However this box does not contain the entirety of the game, the install disk only has the client, or half of the information needed to run the game.


The student's response:

(You have two independent ideas separated by commas. They should be separated by periods or semicolon.)

I'm not completely happy with the sentence but I don't think it should be two separate sentences.

What do you think?