I don' t know whether or not you checked your essay on spelling/grammar mistakes yet but...

Video games have brought up a lot of controversy over the years, but the most prominent issues is the effects of violence in video games.

...the most prominent issues are or the most prominent issue is.

Violent video games have been blamed for several bad things including; School shootings, violent attitudes/behaviour, and depression, but are any of these accusations directly linked to violence in video games?

School without a capital.

People should know the difference between realism & virtual! If they cannot tell the difference, then they should not buy them. That seems like quite a simple solution if you asked me.

I' d write the difference between reality & fiction.
...if you ask instead of asked? me.

Plus, killing people in a virtual reality blows off a lot of steam like nothing else can. Once you have blown off that steam, you have no more steam to blow off, so you are no longer angry. If you asked me, killing someone in a virtual reality is much better than killing someone in real life which more people would do if they didn’t have video games to blow off their steam for them.

You' re using 'blow off steam' a tad too much in that 1 paragraph. Maybe you should look for a synonym.
And again, ask instead of asked? maybe.

On September eleventh, two thousand and one, sixteen terrorists boarded four different flights (four terrorists in each plane). Two of which found their way into the World Trade Centers in Manhattan, New York. One of them found itself in the Pentagon in Washington, D.C. The last plane was found in a field in Pennsylvania. This attack was called the biggest and most devastating attack on America in history. There have yet to be any reports filed that indicate the sixteen terrorists played violent video games that morning.

This paragraph is not really relevant to your essay and I can imagine your teacher might misinterpret it.