The unit can run on a Pi Zero/W, Pi 3B/B+, or Pi 4. I do not know if it will run on a Pi 3A+, it looked like you could mount one, I just don't know if it was intended be used with one specifically. I've played my usual range of games from Atari up to N64/PSX and I've had no troubles. My unit is running on a Pi 4 2GB.
All in all I've got positives to say about it, but that isn't to say there were not some issues.
1. At the time I assembled my unit there was a pre-built image for those using a Pi 4 but those using a Pi Zero/3 you would be having to install the base RetroPie image and install scripts to get everything configured. This probably wouldn't bother most here but having a pre-built Pi Zero/Pi 3 image seems like something that would be an easy one to knock out.
2. Firmware update - There was a Firmware update that was "released" right after (days i'm told from my emails back and forth) that made getting things up and running a bit of a challenge, mostly because the online instructions for doing the update were being updated on the fly and only after about a weeks worth of back and forth were actually at a point where the steps yielded the intended result.
3. SNES button mapping - contrary to what their support email says, for SNES the button labels on the unit are wrong. It doesn't hinder most games, but makes a few awkward. They can be remapped sure, this one annoys more because of the back and forth with their support guy than the actual mapping of the buttons.
Below are a few pictures taken along the way as well as some comparison shots with it next to my two Circuit Sword builds (1 original screen, 1 with the newer screen) and next to the RetroFlag GPI Case.
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