In singleplayer, the criterion "stat.leaveGame" fails to increase by 1 in the current version. It can only be increased manually through the /achievement command. This statistic is tied to the number of times "Save and Quit to Title" is clicked. In all previous versions, the Statistics menu has indicated the actual number of quit games, even in singleplayer.

How to reproduce: Start up a new world in the current snapshot. Quit once, then load the world save. Press escape and click the Statistics button. "Games quit" will be zero.

To see expected behavior: Run Minecraft in the latest stable (non-snapshot) version. Open the same world or another, and follow the "how to reproduce" instructions. "Games quit" will be 1 or more.