Holy Abode of Debauchery. English version

How is it correct to write about an already played game: "Thank you for the game" or "thank you for a game"? I think it's "the," but I'm not sure, because some people write "a"...

"The" is more correct, because you're thanking for a specific session of the game, not just for the existence of a game :)

Added 1 minute ago
Example: you can say "thank you for a game" to a game company, like Blizzard :) IMHO