snowdog on 06 January 2013
Has to be the first Quake, closely followed by Wolfenstein 3D the game that started it all off.
Honourable mentions go to Duke Nukem 3D and Rise of The Triad which had pill power-ups that made things go all trippy and dog bone power-ups that turned you into a dog and allowed you to bite enemies lol. Also had the most secret areas I've ever seen in a game.
