Did you know there are secret animations when using a Super Gameboy?
Eight of the ten borders/frames feature charming animation if you left the controller go idle for a certain amount of time. To access the Super Gameboy menu, hit the L+R shoulder buttons when using a SGB.
Here are all the animations, captured in HD from the Analogue Pocket SGB core. Sped up the timing to make this video as short as possible while still getting the point across. Also listed the approximate idle wait time if you wanted to try it for yourself.
Also, the Gamecube Gameboy Player does not have any Super Gameboy functionality. Just throwing that FYI out there.