I can't speak for whether his games are authentic, but I can say from experience that this seller is pretty poor.
I purchased two marquees from him over the summer - both supposedly on glass. Three weeks after I made my payment, he sends me an email saying I need to pay him immediately or else he'll report me. So, I forward him my Paypal receipt, and three days later, my package magically arrives.
Here's the problem: I was charged $12 shipping, which I assumed covered the packing and weight for two glass marquees. Well, they were shipped priority at $3.85. Even worse, they were just the loose mylar marquees, *rolled up* and shoved into a box. The guy gave me such a run around on refunding my shipping, at least, that I ended up giving up and keeping the marquees (they were nice.)
Buyer beware with this guy.