From then on, it has had sequels, re-releases, and tons and tons of custom content and mods made for it over all these years.
People still make levels, mods, and play Doom even to this day... people like you!
So no matter who you are, or where you came from, let's all wish a happy birthday to Doom!
Keep on Dooming! :toot:

PS: Here's the Classic Doom Complete collection on Steam,
http://store.steampowered.com/sub/18397/
If you don't have the full set of Doom titles, you can probably catch them on sale!