For the curious:
Analogue (not to be confused with the Magazine that features screaming chinks) is a emulator retro console creator. If you try to read through their bullshit, they have retroconsoles with FPGAs in them. An FPGA stands for Field Programable Gate Array - it is a hardware chip you can change the function of the transitors via software ('program it in the field' vs in the lab with equioment). This lets you exactly (or nearly so) recreate console hardware.
This is pretty flippin' cool,if extremely pretentiously autistic.
Their latest product (that john is jizzing his pants about) is a hand-held that can do OG Gameboy to Gameboy advance games, as well as Lynx, Gamegear, and Neogeo; any console 16bit or less is an option it looks like. It plays actual cartridges, and doesn't need BIOS files because They reverse engineered the GB bioses onto their custom hardware.
So yes, if you get a ROM cart, the ROMs should play almost exactly like native. They also support per-game FPGA tweaks - which is where they get a little fucky because again, its not an EMU or ROM dump. They mention down deep in the text you need carts to play,but they definitely are trying to give the impression all the games are included.
Its overpriced and a little Up-its-own-ass, but they include two FPGAs, one for Dev work - which if they have brick protections in place that'd be a fun (if overpriced) little 16-bit FPGA hacking platform.
Its pretty neat, but for John its just a toy to wank about having and then toss into its protective case and forget all about.