Stats are new, and you only have stats for what you've played since they were added.

After I finish a game the stats show I won one game. When I close my browser and and then reopen to play again, my stats show zero games played and the days game is ready play again like I haven’t played it. 

If I leave the screen in mid game it clears when I return. It doesn’t save where I’m up to 

So the problem here is Cross-Site-Cookies, which I'm not about to turn on for a game (it's not that I don't trust the game, it's that it allows all sorts of creepy tracking elsewhere) - it seems to me like the game aught to either store the data in a cookie for the correct domain, or use localStorage.