Raiders of the Lost Ark is one of the best games for the Atari 2600 and I say this without any nostalgia for the title. It's an early adventure game and has a kind of complexity absent in most Atari 2600 games which, based on today's standards, are largely stupid. I've discovered things about this game years later by reading a walkthrough... It has a point system similar to the Sierra games because some activities are actually optional, a breakthrough feature.

In fact, the Howard Scott Warshaw works are great: Yars Revenge, with simple but classic gameplay and E.T., the victim of one of the most unfair public lynchings of a game ever.