Q*bert is an action game with puzzle elements played from an axonometric third-person perspective to convey a three-dimensional look. The game is played using a single, diagonally mounted four-way joystick.[2] The player controls Q*bert, who starts each game at the top of a pyramid made of 28 cubes, and moves by hopping diagonally from cube to cube. Landing on a cube causes it to change color, and changing every cube to the target color allows the player to progress to the next stage.[3]
At the beginning, jumping on every cube once is enough to advance. In later stages, each cube must be hit twice to reach the target color. Other times, cubes change color every time Q*bert lands on them, instead of remaining on the target color once they reach it. Both elements are then combined in subsequent stages. Jumping off the pyramid results in the character's death.[4]
Q*bert hops diagonally down the pyramid to avoid the purple snake, Coily.
The player is impeded by several enemies, introduced gradually to the game:
Coily – Coily first appears as a purple egg that bounces to the bottom of the pyramid and then transforms into a snake that chases after Q*bert. He is often considered the main antagonist and Q*bert's arch-nemesis.[2]
Ugg and Wrongway – Two purple creatures that hop along the sides of the cubes in an Escheresquemanner. Starting at either the bottom left or bottom right corner, they keep moving toward the top right or top left side of the pyramid respectively and fall off the pyramid when they reach the end.[2]
Slick and Sam – Two green creatures that descend down the pyramid and revert cubes whose color has already been changed.[4]
A collision with purple enemies is fatal to the character, whereas the green enemies are removed from the board upon contact.[2] Colored balls occasionally appear at the second row of cubes and bounce downward; contact with a red ball is lethal to Q*bert, while contact with a green one immobilizes the on-screen enemies for a limited time.[4] Multicolored floating discs on either side of the pyramid serve as an escape from danger, particularly Coily. When Q*bert jumps on a disc, it transports him to the top of the pyramid. If Coily is in close pursuit of the character, he will jump after Q*bert and fall to his death, awarding bonus points.[2] This causes all enemies and balls on the screen to disappear, though they start to return after a few seconds.
Points are awarded for each color change (25), defeating Coily with a flying disc (500), remaining discs at the end of a stage (at higher stages, 50 or 100) and catching green balls (100) or Slick and Sam (300 each).[4] Bonus points are also awarded for completing a screen, starting at 1,000 for the first screen of Level 1 and increasing by 250 for each subsequent completion, up to 5,000 after Level 4. Extra lives are granted for reaching certain scores, which are set by the machine operator.