Yar's Revenge (Atari 2600, 1982)

At a distance, this game will appear to be a jumbled mess of information.  The premise doesn't make even the slightest bit of logical sense.  The screen features a block of random flickering pixels, and each character is a distant abstraction of what they are meant to represent.  And yet, Yar's Revenge (1982) is one of the most finely crafted and enduring games on the Atari 2600, and also my favorite on the system.
The game was designed and programmed by Howard Scott Warshaw of Atari.  Most people will not be able to know him by name, but he was one of Atari's more prolific programmers, having also made the adaptation of Raiders of the Lost Ark and, yes, the ill-fated ET the Extra-Terrestrial.  This game is proof that ET's failure was not on the part of Warshaw being an incompetent designer (it is, in fact, evidence to the contrary), but Atari's poor business decisions.  His influence on Yar's Revenge's success is a stroke of genius.  Originally meant to be an Atari port of the arcade game Star Castle, which the 2600 would not have been able to support due to technical limitations, Warshaw changed the premise of the game to make it workable.
The premise is this:  you control a housefly trying to fight off an attack by the alien, Yar.  You may move and shoot in eight directions (highly uncommon for Atari shooters).  First, you must shoot down the barrier the Yar hides behind to expose him, while avoiding (what might be) a homing missile.  That flickering area I mentioned earlier?  That is a neutral zone, where the missile cannot kill you if it touches you, but you cannot shoot.  Once the Yar is vulnerable, you touch him to summon a bomb, and aim carefully to hit him with it, which will blow him up and advance you to the next level.  Be careful through, because without much warning, the Yar may decide to fly out and attack you!
This may sound convoluted in theory, but in practice, it is great fun.  This game actually offers a high level of strategy and fair challenge relative to the other games of the age.  If you shoot from a distance, you are safer from the attacks of the Yar and also the missile.  If you draw close, however, you can achieve greater accuracy and speed, at an increased risk.  You must use the neutral zone to your advantage, and since you wrap around the screen (go off one edge and you reappear on the opposite) it can be used to make quick escapes from the missile, which grows progressively faster with each level.
What Mr. Warshaw created is one of the greatest games of its day.  While other Atari games age and/or rot around it, Yar's Revenge stays fresh and fun.  Compare it to his other titles.  While Raiders of the Lost Ark is generally considered to be better than ET, it is still archaic, cryptic, and in some places, dysfunctional.  Yar's Revenge, on the other hand, shows its age only in its visuals.  Howard Scott Warshaw has been unfairly criticized for ET, whose flaws are mostly not his fault.  He ought to be celebrated for the enduring classic that he created.