Personally, how I see it, it isn't a problem. technically it isn't even a duplicate icon. They're two different icons for two different programs, one is the launcher and one is the game. It's working just how I'd expect it to. Unless the launcher is combined with the game itself, it seems like there's going to be two icons, because they're two seperate things.
Besides, both the icons aren't even up at the same time. When the launcher is done, it launches the game and closes. The only things up for Blockland then, is the command prompt and the game screen. Which as far as I know have always been seperate. And nobodies complained about it before