You can find this review in full at GBAtemp.net:
https://gbatemp.net/review/retroflag-gpi-case-2.1991/

In this modern age you can emulate your entire retro library on everything from your phone to your fridge. Despite its significant accessibility, many retro fans are left longing for the perfect way to play. Some want an all in one console to leave hooked up to their TV. Others want something they can pull out of their bag and play for ten minutes at a time. And there are those who just want a blast of nostalgia. Aiming to please all three of these crowds Retroflag is back to iterate on its popular GPi Case, now compatible with the more powerful Raspberry Pi Compute Module 4.

For those completely out of the loop, Raspberry Pi systems have long-been an affordable and effective means of retro emulation. With popular Linux distributions such as RetroPie and Lakka making the playing of these titles seamless and really quite stylish once setup, it’s easy to see why so many turn to them to fill this niche role. So where does Retroflag fit into this equation? In order to make Raspberry Pi gaming portable, they’re back with an almost-all-in-one solution wrapped in the image of Nintendo’s own first handheld. At a glance, it’s magnificent.

Though a bit smaller than the original Game Boy, coming in at a size closer to the Game Boy Pocket, I think Retroflag have absolutely nailed the look and feel of this classic console. The plastic, the buttons, the D-Pad, even the rubber start and select buttons. They’re all here and they feel so brilliantly close to the real deal, even matching up the volume slider, contrast slider, headphone jack, and physical power switch to their proper locations. The screen is, as you might expect, a notable improvement on the original Game Boy, coming in at 3 inches from corner to corner. As well as this, you have two bonus buttons hidden in plain sight at the front of the device for turbo and home functionality, as well as an X and Y button for additional retro compatibility. Hidden quite out of plain sight however are the L and R buttons, built into the case itself and being the only real questionable standout. They’re just a bit awkward. I understand wanting to keep the integrity of the original Game Boy form factor to an extent, but I still think I’d have preferred something closer to Anbernic’s RG351V, where there’s a ridge on the back for your fingers to rest on. If you’re playing games that only make light use of the shoulder buttons though, they do fine. You need to get into the habit of pressing on the front of the case as you press them in to maintain a grip on the device, but if you’re just, for example, changing boxes in a Pokemon game, you’ll get by.

Installation of the board into the case is as simple as popping off the top of the case and slotting it into where the cartridge would sit. It’s quick and easy, with access to this area not requiring a screwdriver. Having said that, with just five Phillips head screws holding the back of the case together, it’s incredibly easy to remove if you’d prefer to have more space to work with. Though I had no issues removing the board and putting it back in, it should be noted there really isn’t much room where the board actually fits into the device, meaning your options for heat dissipation are really quite limited. This unit being sent to me by Shaun after he finished his first impressions post, it had a small heat sync installed already. I haven’t run into any heat-related issues in the time I’ve been using it myself at least. You will need to take care when inserting and removing the Micro SD card, with the case opting for a bit of an awkward latch in oppose to a more common spring-based eject system. It’s awkward but you do get used to it after so many removals.

The screen is really quite nice. At 3 inches with a 4:3 aspect ratio, you’re set for some sharp gaming on a good chunk of common retro consoles. Outside of this though, I found the borders on the 3:2 GBA games and 10:9 GB games to be perfectly fine when playing. You can of course have these games stretch to the full size of the screen when playing, but this is a particularly hairy point of contention among retro fanatics. You have nice control of screen brightness via a physical slider where the contrast slider once sat, which is analogue in nature. At least I think that’s the correct terminology. If you scroll it all the way down, you’ll hit a limit and you can’t scroll it anymore. I like it a lot. 

When comparing this to the original GPi Case, the most significant upgrade will naturally be in the performance. Where the original case could only house a Pi Zero, and later a Pi Zero 2, this model comes sporting support for the latest and greatest in ultra portable Raspberry Pi boards: the Compute Module 4. This is ultimately a Raspberry Pi 4 stripped down to the essentials, and boy does it show.

All your usual retro giants run as expected. As a Nintendo junkie myself, I’ve enjoyed NES, SNES, and all the Game Boys in this compact bundle of nostalgia. Looking past that though, it is capable of more, even if the controls available aren’t exactly tailored to it. What this handheld lacks is an analogue stick, and while the lack of stick contributes to the original Game Boy aesthetic, it puts a lot of the additional power on offer to waste. Sure you can remap controls in RetroArch to have your D Pad act as an analogue stick; this does work fine for the most part. Especially with N64 games where they’re largely designed to use one of the stick or D-Pad, but it isn’t ideal. It’s worth mentioning here that I also never managed to get this to work. Though I tried to play Sonic Adventure 1 and 2 on the system, and they seemed to run well, I couldn’t move, and I couldn’t figure out what was wrong in the settings. In all likelihood this is me not finding one specific thing that should or shouldn’t be enabled, but it does take away from the larger ease of use.

Though you can’t comfortably play these games on the go, the GPi Case 2 does put this power to use in other ways thanks to a dock that comes with the deluxe edition. It’s not exactly as seamless as the Switch’s hybrid capabilities, but it’s an interesting offering on a device like this. First and foremost, there’s no quick switch between handheld and docked play. To dock the system, you need to turn it off, and turn it back on in the dock. The same is true when going from docked to handheld. I do like the idea of the dock, but the lack of ability to fluidly switch from playing on the go to on the big screen is a bit of a disappointment. Having said that, it does enable you to utilise the fullest potential of the CM4 that the limited controls of the case would struggle to accommodate. It’s less of a hybrid system, and more of two standalone devices in how I view it. It does beg the question though: would you just be better off with two standalone devices?

It’s difficult to say. With Linux-based handhelds only getting more competitive and even older PCs that you may just have lying around being able to match this kind of performance when hooked up to a display, there’s certainly a case to be made for going down that kind of route. Devices like the GPi Case 2 are what I would call an extravagance. Make no mistake, it does achieve what it sets out to comfortably, but it’s overspecced for the things it does best. The real allure of this device to me is in its portability and faithful recreation of the Game Boy’s original design but in this faithfulness, or more precisely its lack of analogue stick, it finds itself unable to live up to its fullest potential.

I still do recommend it though. If you’re wanting a plenty powerful device that looks and feels like a slightly more compact Game Boy this is an absolute dream. Just make sure you can source a CM4 board beforehand, since it’s not included in the kit.