Epilogue, manufacturer of the GameBoy emulation tool GB Operator, has revealed that the peripheral now works on the Steam Deck. With the Operator, you can effectively play your GameBoy (original through Advance) cartridges directly on your Deck via the dongle.
The GB Operator has been available since August of 2021, and was originally designed to work on any PC running Windows, Linux, or MacOS—this specific Steam Deck config naturally has a higher buy-in cost. The Operator builds on the open-source mGBA emulator, as opposed to the hardware-level FPGA solution you see in the Analogue Pocket or the MiSTer.
Emulation is typically held to be the lower-fidelity way to run games sans original hardware, but it is also cheaper and more accessible: The Operator will run you $50 vs. the Analogue's $220, while constructing a MiSTer is a super cool but potentially challenging DIY undertaking. The mGBA software in use by the Operator, for its part, seems to be a highly-regarded emulation tool.
Compared to just installing mGBA on its own, which works great on Steam Deck, the Operator lets you skip having to dump a ROM from your cart before playing it. Should the novelty of playing games directly off the cart wear off, the Operator does provide a convenient method to flash and dump ROMs. Similarly, the Operator also lets you transfer saves between your computer and the cart.
The Steam Deck's always struck me as more an inheritor to the legacy of the Game Gear or the PSP, you know, the bigger, high-powered, black plastic, rectangular challengers to Nintendo's handheld throne. Still, this feels right somehow, and it doesn't look like Nintendo's going to offer an official GameBoy emulation solution any time soon. Between this and the Deck's potential as a Wii U/Nintendo DS emulator, Valve's portable gaming PC is proving to be quite the retro gaming powerhouse.
The Deck certainly strikes me as a more fitting home for GameBoy emulation than a desktop or, God forbid, the Android smartphone I used to play Fire Emblem a couple years ago. I picked up a Mario and Luigi: Superstar Saga cart awhile ago, and I'd love to replay that old favorite on my Steam Deck.