I recognized HL1, HL2, Doom 3, BioShock, Minecraft, Far Cry 1, and Portal, and that's only because I own those...
Two thoughts: If Minecraft counts as a FPS, then wouldn't the Elder Scrolls count as well? ;D
When Freeman makes it to HL2 (which is clearly inevitable), I think it should be named "2 Freeman's Mind"
as a sort of reference to the objective in HL2 being 'to free man's mind'.