Due to unexpected circumstances it took longer than anticipated, but it's finally there: you can buy the PewPew M4 from Makerfabs here: https://makerfabs.com/circuitpython-pewpew-m4.html
It comes all soldered up and programmed, you only need to remove the protective foil from the plastic parts and screw together the case. And put in two AAA 1.5V batteries, which are not included.
It comes with CircuitPython 5.0.0 pre-programmed, and several example games. It will run both µGame and Pew Pew games.
From what I can see in the photos (I didn't get one from this batch yet), the only difference from the test units is the black silkscreen and v-cut PCBs — so you might need to use a file or sandpaper to get rid of some uneven edges on the PCB.