First off, your introduction sentence is very dull, flat, and does not make me want to read the rest of this paragraph at all. You always need an intro to be exciting so that the reader will continue reading.

Also, you use both "can not" and "can't." Typically, conjunctions are used with informal writing, and using the two separate words is used in formal writing. Decide whether you're writing formally or informally, and then use just that form instead of swaying between the two.

Your first and second sentences are both the same length, and also both very short. Use sentence variation to make it flow smoother.

In your second sentence, there's no elaboration. WHY can't video games teach people to kill? What leads you to believe that? Your seriously lacking in detail.

Good example using a real person, but who the fuck is Devin Moore? Maybe say "For example, a recent case of video gamers being violent in real life is...." Also explain why the video games are being blamed. I need reasons, otherwise there's no way I'm going to believe you.

What article are you talking about? Suddenly you say "the article states..." but I don't know the name of the article, what it's from, and you have no citation. If you're going to mention an article, you have to cite it.

How does it show that violent video games can't affect a person's mindset? How did you reach that conclusion? What evidence do you have?

There is no concluding sentence. Nothing to conclude this idea or paragraph. You really, really lack sentence variation. Your beginning thesis is dull, flat, and three points are not clearly stated. More detail and evidence is needed, you did not explain "how" or "why" for anything. Your paragraph was very dull to read, it was all over the place, you did not cite your sources, there was a severe lack of detail, and it was extremely elementary overall.