Read the comments two months ago and it's clear he's still working on the game. If it was a con, he could just have pretended to not see all these comments, but instead Adam Dubi replied with a very long and detailed response about his current progress in the game that is obviously not just fabricated.
Also, the sheer amount of detail and passion that is on display in chapter one alone makes it pretty clear that it's not just some scammer - they would try to maximize their time by making something a lot less detailed.