I think it's one of those situations where it's like, yeah I appreciate that it's just one dude, but for me as the player, that doesn't actually affect my enjoyment of the game, so there's only so much I can ignore that stuff. The problem is that I already felt "done" and moved on from SDV (actually I was never that into the game, which is also a factor to being disappointed here) and this just feels like, we're gonna get another few years of the same thing..
Plus, we don't know that the sounds/tileset aren't just placeholders to allow him to release the trailer's vertical slice! I appreciate that this is unlikely, but still! What we recognize as normal development practices don't necessarily apply to a studio of one.