Super Mario Bros.
Of all the games I have played, Super Mario Bros. is the most perfect.
That is all there is: from level design to in-game physics, enemy placement to game length, secrets to mundane running through, replayability and difficulty, Super Mario Bros. is perfect. It is the ultimate example of craft as art, and when viewed on its own merits may very well be the best game ever made. I can only think of perhaps two other games that even approach this one in terms of design, and they are no where near as old as this one.
Why is it only Number 25 on my list, then? Well, this is about favorite, and Super Mario Bros. is not my favorite game of all time. If this were a list about the best games of all time, it would all look a bit different and this game would finish in the top 3, minimum. Still, this game right here is my favorite 2D platformer of all time, and no matter how long I stare at it I can find no fault in it.
Think nostalgia blinds me? Not so. I only beat this game, for the very first time, in the winter of 2009. Over two decades of my life were spent with this game's shadow hanging over my head, and when I finally sat down to beat it I was treated to the tightest, most cohesive gameplay package in my experience as a gamer. It is superb, and if you think otherwise then - well I can't imagine disagreeing more with someone about a video game.