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IDSPISPOPD, IDKFA, and IDDQD work but the only weapons that work are the chainsaw up to the rocket launcher.

The shareware weapons. You had to fork out some real cash for the full version if you wanted the plasma weapons!

That might be why the plasma rifle and the BFG don't work if it embeds a shareware WAD file. See also: https://archive.org/details/DoomsharewareEpisode