Divine Souls. The game has been out for only a little while, but the team is apparently unhappy with the reception thus far, not to mention the game's bugs and other instabilities. So without any major notice, the game has been essentially put on hiatus, going offline so that the team can put it back on the drawing board for more refinements and adjustments.
While the game has already been taken down, there's no set timeframe for when it will come back online; the closure notice acknowledges that it may be some time before the bug fixes and refinements are complete. Players will receive a partial refund for any in-game currency purchase since the game's launch, with the amount refunded dependent on how close to the closure it was purchased. It's not an ending, just a pause, but it's still sad news for the game.
[Thanks to Paul for the tip!]