You should get yourself a right-angle USB-C cable that sits snug to the side of the G&W. It really improves the look as a desk clock!
I also use mine as a desk clock, and I love it!
Actually it’s really easy.
Go buy some silver metallic vinyl transfer foil from Amazon. Like $10 for enough to fix 200 game and watches with this issue. You can also buy polarizing film as well.
Works fantastic and twenty bucks will get you supplies for years.
Silver Metallic Foil HTV Heat Transfer Vinyl for Tshirt and Apparel 12" X 10"( Pack of 5 ), Easy to Weed and Iron on, Guaranteed Size https://www.amazon.com/dp/B07CTT1Q47/ref=cm_sw_r_cp_api_glc_fabc_aqx1Fb37S4R5T?_encoding=UTF8&psc=1
Edit forgot to add: Just realize the foil in a game and watch is actually a reflector AND a polarizing film together so you need a reflector and polarizing film behind the lcd and another polarizing film in front of the lcd and art.
if that's all you want then grab one of those cheap tiny Gameboy emulator things off amazon. you can load Pokémon on to it and be good to go. some of them are cheaper than the G&W. This one even looks like the G&W.
You don't need RetroArch to do this. You can just use ordinary MAME, and you don't need to do ANY of the stuff mentioned in this guide, the games just work. Using RA to accomplish this adds several unnecessary steps. Head to http://mamedev.org to download the latest version of MAME. It's much easier.