Developer Rebecca Ann Heineman has put up Doom’s source code for the 3DO up on Github, to coincide with the game’s 21 year anniversary.
Rebecca also wrote on the github about the difficulties she had making the game. Much like Howard Scott Warshaw making ET for the Atari 2600, Rebecca was pigeonholed into making the game on a tight schedule, and was forced to make a lot of compromises.
You can read the whole thing (and download the code if you’re inclined) here, but here’s how Rebecca (a veteran who worked on games like Another World and The Bard’s Tale 3) starts her story:
I was told that there was a version in existance with new levels, weapons and features and it only needed “polishing” and optimization to hit the market. After numerous requests for this version, I found out that there was no such thing and that Art Data Interactive was under the false impression that all anyone needed to do to port a game from one platform to another was just to compile the code and adding weapons was as simple as dropping in the art.