Isn't it always embarrassing when your parents break out the baby pictures? Well, spare a thought for the 21-year-old DOOM. In celebration of the classic shooter's anniversary, Id co-founder John Romero has spent the last couple of days releasing never-before-seen early assets from its development.

These aren't just of historical value, either. For the still very-much active Doom modding scene, some of these images mean new semi-official textures that can be used in future WADs.

You can see some highlights over the next few slides, or find the entire collection over at John Romero's Twitter account. Head here for a Dropbox link to high-quality versions.