Development for Doom started in November of 1992, and was released in December 1993. Development for Star Wars: Dark Forces started in September of 1993, and was released in February of 1995. Midway through the development, mods for Doom came out where you could play on the Death Star, prompting the developers to make changes to the original plans for the game. The game /was/ inspired by Doom, but in a smaller way than most people realized. So, his statement that development started before Doom was incorrect, but the game was in development before Doom's release.
Heh, I fixed Gromas Mines so you can't clip the thermal detonators to kill the Dark Trooper and so that the exit tunnel switch can't be activated from within the tunnel. Obviously the fixed map isn't used in speedruns, but good times.
