Doom for SNES full source code released by former Sculptured Software employee
gbatemp.net
gbatemp.net
But it was uncompilable because of copyrighted assets/code. This seems to be the full source which includes the missing stuff.
[0] https://gbatemp.net/threads/doom-for-snes-full-source-code-r...
The level geometry of this version was more complex than the PlayStation port, and it even had online multiplayer support.
One interesting difference though is that enemy sprites only face the player.