TSC already covered alot of this but I spent a while writing it last night before passing out so heres what i wanna know anyway.
I'm glad the link port is there albeit in a pretty bad location, but no sync would be huge. And so much focus on the brightness buttons when that knob has its own area code 
A few questions I'd like answered, if possible:
Do you have photos of anything running on this? I was shocked by no photos of it powered on as that's unusual for hyperkin
Any idea on charge time?
My god that screen, please no. Tell me you can center the image, or will it be stuck stretched like my 1st gen supaboy? I know square LCD's may not be in great supply but ideally the final revision would physically cover the black bars from view. Nobody liked that on the original supaboy either. You didnt hear the end of it on every post containing it, yet somehow here we are again.
The back-light. Assuming that unsightly giant dial is for volume as its the only dial visible in Neowin's photos, and a "blue backlight" feature is listed in the display case, was the RGB backlight ditched? Otherwise, if thats the "RGB dial" mentioned in the prior thread its pretty needlessly huge and detracts from the look.
Sound accuracy. You're aiming this at a group where some are picky about even the CPU revisions of the same model of Gameboy. How is sound accuracy being ensured and what model is it most comparable to? How clean is the output compared to a prosound mod system?
Is the inclusion of LSDJ built in and an SD slot (not seen) to export songs still planned?
Not a question but oh god please do something about that logo and hideous knob
I've been really excited about this since seeing the first prototype but I'm starting to feel like you may as well have just sold the metal shell that hyperkin pretty clearly just tossed a teal-backlit GBP into for the last prototype. Hell I'd still buy the hell out of that.
This is slowly looking more like what I'd expect after my first gen supaboy and the absolutely painful to use smartboy. After buying that "devkit" then seeing nothing but a change to USB-C in the final product, I'm not sure why I had such high hopes for this now.
You can tell some at hyperkin want this done right while someone in a suit wants to ride the wave of January's free press from the backlit GBP before it dies down.
It pains me to speak negatively about this thing as I have such high hopes for it, but these things need to be done right, or its just another clone system.
I hope that this chunky device is just a prototype and we see design fall more back in line with what we were previously shown and told about. Right now for me, this is a no-buy.