Back in July, we reported a discovery that the Switch had a built-in NES emulator, probably for future Virtual Console games. The people who discovered the emulator kept digging around, and found a game that’s hidden inside the Switch firmware.
The game is Golf for the NES, but it’s called “Flog” in the firmware system, which is “Golf” spelled backwards.
The NES Golf game on the Switch is fully playable with the Joy-Cons, and even supports two players. However, there is no way to access the game from the Switch operating system.
It’s likely that Nintendo added this simply to test the NES emulator on the console, but it’s interesting that they would leave it in for the final Switch console firmware.
Here are some screenshots of the NES Golf Switch game: