John Harris argues that a signature of Atari games is '[a]n emphasis on procedural content as opposed to hard content.'
Atari was more likely to give the player algorithmically modified, changeable levels than hard-coded sequences. Gauntlet gives players different levels from a pre-made set every game, and manipulates food power-ups depending on game difficulty, average score per coin, and number of players.
While it always goes through the same general areas, Toobin's level order and layout can be quite different depending on which forks are taken. Skull & Crossbones shortens levels on easier difficulties. Atari Tetris uses the high score initials as preset blocks late in the game.