Good map. Very id-like and even Doom-like in places. Quite claustrophobic in design but paired with not particularly challenging enemies works pretty well. Pretty relaxing to play through.
Might have benefitted from some other base-style enemy varieties from progs_dump or Alkaline but then I wouldn't have been using Copper. :)
Video of my blind playthrough here (Copper mod, Nightmare). 4 out of 5 secrets found. Hunted for the last one for a while then gave up, so the actual playthrough ends at around 12 mins and the rest of the run is me running back through shooting lights and walls to no avail.