The Ontological Argument Debunked?

I'd like to preface this by stating that I'm not an atheist, but this particular argument for proving God's existence had me immediately skeptical. If you're in the mood for something more philosophical on G@G, stick around :)
I couldn't exactly put into words what I felt in my gut was 'off' about this, but I found this man on youtube who must have at least a 1,000 point IQ who came up with a video debunking the argument, and I agree with him on most points. Although he didn't directly break down the logistics in the first video, they can be applied to the first video for the most part.
What are your thoughts? I'm going to steal one from @Secret660 (forgive me, I know that's not her username) and say PLEASE be detailed in your answers! :)
The Ontological Argument Debunked?
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