[qwertyuiop924]

True, but Duke Nukem 3D did the same thing (actually, id didn't release any tooling for Doom: id's internal DoomEd was written in Objective-C for NeXT machines, so it wouldn't have been much use in any case. They didn't start releasing their internal design tools until a bit later, meaning that DN3D did it first), and DN3D's community is virtually dead, while Doom's continues to thrive.

[blakeyrat]

I was about to point out that Marathon: Infinity did it first, but it turns out DN3D beat it by about half a year. The fact that Marathon: Infinity included the game editor on the disk was a huge deal at the time though.

Obligatory name-dropping of Marathon, the greatest game to be virtually ignored by all gaming analysis/histories.