Any one think if including Alone in The Dark? This started the whole survival horror thing, and without this there would be no Resident Evils, Parasite Eves, and Silent Hills etc. etc. (getting a little crowded now)
Also, what about Defender of the Crown? this game sold a lot of Amigas. The graphics alone made people buy them.
And I know it sounds weird but Mario 64 should be included. This was a groundbreaking game and got 3D platformers off to a rolling start. (I know Jumping Flash on the PS was the first 3d platformer, but I think M64 gets the credit for what it did to the genre)
The trouble is when defining lists like this, you need to state the system that it was released on to bring relevance to the game.
Wolf/Doom for example both helped define FPS on the PC, however, consoles never had the same fate. Wolf and Doom on console made very little impact at all, but Turok really turned the Console FPS on it's head. Another fave is Goldeneye which was a major influence on multi-player console gaming. It was the first FPS ever that could be played 4 player without the need for extra hardware and it was the first FPS that meant that shots to different parts of the body do different amounts of damage.
I could rant on but it's mothers day tomorrow, and I need to get to the shops quick!