I never thought I'd be 'that guy' that dismisses a list because of my faves being excluded, but honestly, I just can't understand the thought process behind this one when it doesn't include Doom.
Especially when a major criterion is that the games 'still hold up' -- Doom is 22 years old, is a seminal title that's credited with starting the explosion of the FPS genre, and yet it's aged incredibly well. Doom still gets played today by tons of people, still gets hugely ambitious mods released for it, and still has new level packs released constantly by the community.
Hell, if you want to go more modern, at least put one of the Quakes in there, or Duke 3D or something.
But no, instead we get goddamn COD and Battlefield 4 of all things, and of course Half-Life 2, which I'll grudgingly accept since so many other people love it (but for me it's one of my biggest gaming disappointments).