I too am pretty impressed with the graphics. This is probably due to the fact that many of the games done by people have, at best, "acceptable" level graphics. The ones that stand out are those graphics done specifically by artists (such as those games created by a team like GuildHall or the Forest tileset, which is pretty much just created for the graphics). This picture looks more like a real game than many of the things I've seen so far (from a purely visual appeal standpoint) or things that I myself have attempted. That's one of the reasons why I've never actually made a game with SGDK.