The requirement to put a GBA game in is because, as an anti-piracy measure, the Game Boy and GBA won't boot games unless there is data to display a Nintendo logo inside the cartridge, and this is probably an unlicensed accessory, meaning they couldn't put the data to display the logo or else they can be sued by Nintendo. So it reads the logo from a separate, official cartridge
That’s actually a neat accessory; 40-60 seems all right. Sound seems kinda hit or miss a bit although that might be a Famicom sound chip thing. Have you seen anything similar for the Super Famicom?
By the way, could you mute the background music while playing a game with the game audio? It's distracting to hear the background music and the game audio in the video at the same time ^^ Thanks
I would like to see a video where you tale this apart and use it on the Gamecube Gameboy Player and Analog Pocket assuming it'll work that way since in theory there'll be nothing in the way blocking it.
For the ds lite there is another version of this, which i have, is called "famulator" and it has some improvements like been able to use the DS lite power adapter so you don't need batteries, also can be plugged to a tv via AV cable included. The dowside is that it fits only on the DS Lite 🤷🏻♂️