You should change the site to https version imo, I don't know what the exact reason but whenever I try to access the site by the link you provided it always shows "522 error" (IIRC). I need to search it through google first to be able to access it.
It seems that the game is built only for windows, I didn't see any other devices are available when I downloaded it, or I missing something here? And unfortunately, it's not fully free to play. We need to pay the subscription 1 Euro for one character per month (2 lites at the initial phase).
Anyway, it should be posted at
Service Discussion (Altcoins) instead of here and thanks for sharing it.