Zoop is a real-time puzzle game, like Plotting, where the player controls a triangle in the center of the screen. Every second (or more often in advanced levels), a piece comes in from the side and possibly pushes other pieces forward. Two consecutive pieces will never come in from the same quadrant, and runs of consecutive identical pieces on one row are longer, statistically, than one might expect. If a piece falls into the center square, the game is over.[11]
If the player shoots a piece of the same color as their triangle, it will be "zooped" (cleared) and points are earned. If the piece behind the target piece is also of the same color, it is also "zooped". The same goes for the next piece, and so on. If a piece of a different color from the player's current piece is shot, the player's piece will switch colors with it. This is also what happens when a piece of a different color is encountered after zooping one or more pieces of the same color. When the quota of "zooped" pieces is met, the game speeds up, and (before level 10) the background changes. Various special pieces do different things, such as a proximity bomb (shaped like a lightning bolt) that blows up pieces in a 3×3 area centered at the target piece, or a line bomb (often shaped like a gear) that clears a whole target line of pieces.
To make gameplay more difficult, the game also employed what was referred to as "Opti-Challenge" backgrounds. As the levels progressed, the backgrounds would become increasingly distracting. Early on, this would involve the use of contrasting colors and increasingly intricate color schemes. Background patterns would also become more intricate and would make subtle use of asymmetrical elements. Although the "Opti-Challenge" technique of the game was used as a selling point, very little information exists about the technique itself, and no other game on the market has ever claimed to use "Opti-Challenge" graphics. The sound effects have a cartoonish tone to match the vivid colors used through the stages, while the music is smooth jazz and "evolves" with the game. As the levels get harder, the music becomes more tense, adding to the fast-paced atmosphere of the game.