Wolfenstein 3-D definitely gets the credit, but Doom took it SO much further and was the first game that really brought out our gaming-kid excitement through fear and suspense even despite, in retrospect, it really just being a puzzle game with exploding demons (and when you get into the history and documentaries, it’s wild what they actually wanted to do in the engine, but the consumer level performance limits at the time cut into a much more in depth experience).