Pitfall! is considered the first major platformer, and an important piece of video game history. The game was released in 1982 for the Atari 2600 and soon found its way to the ColecoVision, Commodore 64, Intellivision, and Sega SG-100. I think the game is also playable via GameTap, but who cares? It was the second biggest seller on the 2600, surpassed only by Pac-Man. Unfortunately, Pac-Man on the 2600 is one of the worst games ever made. Pitfall!, however, is amazing.
You control Pitfall Harry through a jungle, jumping over pits of tar and water. You can swing from vines, jump on alligators, and collect treasure. Pitfall! has a unique game mechanic: you only have 20 minutes to beat the entire game. The perfect game results in only 1:42 seconds left on the clock... so you've almost no time to enjoy the detailed landscapes. You can complete the game by collecting all 32 treasures scattered about the jungle. Don't expect an ending, however. When you beat the game, everything just stops moving.
The world of Pitfall! is composed of 256 screens, each with some combination of pits, animals, logs, treasure, fire, and vines. The player can choose to progress through the game in either direction, but it is generally easier to move from right to left. Occasionally, you will have access to underground passages infested with giant scorpions. These passages allow for extremely quick travel: each underground screen corresponds to three above ground screens. To complete the game, you must use these passages.
Collecting treasure adds to your score, while tripping on a log or falling down a hole reduces your score. All the other obstacles (including the water and tar pits) simply kill you, and you have three lives (and are unable to collect more). A perfect score is 114,000 points.
Pitfall! was created by David Crane (who also made A Boy and His Blob, a similar game... sort of), and the famous anecdote is that he designed the game in 10 minutes and programmed it in 1000 hours. He probably could have spent a little more time in planning, but, I must admit, Pitfall! withstands the 27 year test of time.
My friend had this game, and I remember swinging across vines and jumping on alligators. However, at the time I didn't have the benefit of the internet and we had no idea what the goal of the game was, other than exploring. It was fun, but completely eclipsed by the fluid gameplay and fantastical world of Super Mario Brothers.
Pitfall! was a technological accomplishment upon release, proving that the Atari 2600 could make games that didn't look like garbage. Activision has tried to update Pitfall several times, resulting in several abominations (Pitfall 2 is pretty good, but I haven't played it much). Ironically, the installments with the least technological advantages proved to be the best games. As with many classics, Pitfall! possess an almost supernatural magnetism. Play one single game of Pitfall! and tell me you don't hunger for more.