Overall I’ve had a great experience with the product. I had 3 minor complaints:
1) I had a lot of issues getting the GB and GBC rom files to display on the menu after booting up the cart on my GBA SP or Analogue Pocket. It took a couple of hours of trying various troubleshooting steps online (none of which worked). I only got it to work randomly after I accidentally added all of the GB and GBC ROMs as 7zip files. After I unzipped them and reloaded the cart, all the files appeared and played fine.
2) NES ROMs have A LOT of issues for me. Graphic corruptions, pixels not aligned properly, audio corruptions. Normally I wouldn’t have mentioned this since this is a GBA flash cart, but it’s advertised that NES ROMs are supposed to work. This was definitely disappointing to experience.
3) No upscaling options for GB and GBC games. This isn’t a huge deal on my GBA SP, but when playing on the Analogue Pocket, only having the original aspect ratio Is very noticeable vs playing an original cart on the pocket (which gets beautifully upscaled to fit the screen). Now, I know this product came out well before the pocket, so this is more of an improvement idea to consider for future iterations of this product.