Has anyone else seen this? It seems back in the day work was done on an NES port of CC, but it was abandoned:
As mentioned in the article, this version contains a level unique to it. (It is actually the last nonsecret level.) I have ported it to .dat format here:
Note that the above article shows a map of the level which isn't completely accurate, and in particular I don't think the level is solvable as depicted. (The real level is, though.)
Some more notes about the NES version:
The NES behavior is similar to Lynx, including the presence of block slapping.
You can press Start to pause/unpause, and Select to restart a level.
The article mentions that you can press A to skip to to the next level (when the level is shown but before you start playing). Pressing B lets you go to the previous level.
The decade messages do not generally show up at the end of decades, and the levels following them are not necessarily the usual ones.
The typo in the hint for Open Question is fixed.