I have few options for you here, although I have never paid for an online game with cryptocurrencies:
search for some Japanese websites and games, because many Japanese stores accept cryptocurrency payments these days.
Try
Microsoft. It has been reported, that Microsoft accepts payments in bitcoin for purchasing games.
Exchange your bitcoins to fiat and you can pay anywhere you want!
Go to a dating forum, create an attractive profile and announce that you own bitcoins (lots of girls will be interested, if you are a guy interested in girls, and vice versa).
This will be an interesting online game to follow, lol
Have fun!