I'd think that if you were serious about selling a stack of games for $20,000 that you'd list all of the games in the body of the message. With no list and without individual pictures of half the games in the first stack indicates to me one of two things. This guy would quite possibly rip you off and only give you some of the games in that stack, or that this guy either doesn't actually want to sell his stuff and is being forced into it by somebody else and is intentionally making the shadiest auction he can.
"Baby, I tried to sell my games, but they just didn't sell. Nobody wants them. That's what they're worth, I'm not going to just GIVE them away!"