I'm concerned with the lack of sharpness that is apparent in all the example videos. He claims it's not an inherent limitation of the camera but just down to his photographic skills. But since he designed the entire camera that doesn't really put me at ease. Also, all the videos look soft in the same way.
Most cameras do a lot of post-processing to produce "nice" images - could be there isn't any of that (yet) and/or there is filtering to do noise reduction - remember thet exposure times are very short.
Looks like a nice piece of engineering - keep it simple. I would have liked to see a jog dial and external trigger in & strobe out though - I suppose these could be added as it looks like the UI software part is open.
Being able to select footage in-camera for save is definitely the way to go, as you usually only want a very small subset of captured data.
Quick reality check :
Flash memory is a Micron MT29F128G08AMCABH
Only skimmed the datasheet, but a quick reality check on write speeds :
350uS per page (8192+448 bytes), 2 planes per die, 4 dice per device, 2 devices = approx 395MbytesMBytes/sec.
VGA 640x480x840fps=258Mpixels/sec
So in the right ballpark, probably with some compression
Looks like sensor is
Onsemi Python