5) Tetris (1984)
Tetris is the very model of simplicity. The computer equivalent of Snap or Draughts, Tetris is now omnipresent on pretty much every hardware format known to man – seriously, there are probably kettles that can play it.
How has Tetris endured to this day? Well, it's incredibly easy to pick up and understand, yet the building challenge creates such an addictive edge that you can't help but keep plugging back in and polishing off your high score. The Game Boy version remains the best, but if you don't own it on your current smartphone, you're a fool. Great music, too.
4) Super Mario 64 (1996)
Transferring two decades of 2D, side-scrolling platform knowledge into 3D? That might seem a daunting task to any other studio, and sure enough, some characters made missteps (looking at you, Sonic) – but it was a piece of cake to Nintendo, as evidenced by Super Mario 64.
Has there ever been a better system-selling game in history? We think not. Super Mario 64 established the template for 3D platforming much like its predecessors did for 2D, with dazzling worlds, creative challenges, and such an incredible amount of insanely fun things to do. And it's still a blast to play today, no less.
3) Half-Life 2 (2004)
Half-Life 2 is an astonishing game on every level, from the combat to the puzzles, the writing to the sound, to the original and convincing design of its world. But perhaps best of all was the fact that you could pick up a circular saw blade with the Gravity Gun, shoot it at a zombie's neck and watch its head pop off like an overripe, brain-filled coconut.
As first-person shooters go, this could remain the greatest for another 10 years. And it could well be that long before we finally get a finale to the story, given Valve's track record over the last decade.
Still, even if Half-Life 3 never surfaces, we'll always have our memories - and what memories they are. Has there ever been a spookier, more tense level in any game than Half-Life 2's Ravenholm? No way. Has there ever been a better weapon than the aforementioned Gravity Gun? Definitely not. Has there ever been a better, more varied cast of adversories to battle past than the assorted head crabs and antlions and striders and zombies of this game? Not on your nelly.
In short, everything about it is near perfect and if it ever gets a PS4 or Xbox One remaster we'll be all over it in a shot.