This is a neat idea. The thing I dont like as an investor is, if I do not play the game, My purchase is only worth 10% of what it could be right? It seems like the inflationary nature of this is pretty huge.
While the mining process is seamless and uncomplicated, one cannot mint DGS tokens at no cost. Each time you successfully complete a game level, you must pay some gas (ETH) for Dragonglass tokens to be mined (transaction to be made). In other words, there's economies of scale at play: you can mine 10x DGS tokens out of very small amount of Dragonglass but, because of gas, returns will be comparatively low. And vice versa: the bigger the initial mineable amount of Dragonglass tokens, the better gas:mined DGS ratio.
Also, part of DGS tokens, that will be used to play the future Dragonglass games will be locked up.