The exact rules of the game vary depending on versions, but a general summation of the game is as follows. The is being presented with a grid, somewhere on which is the opening of a pipe. Liquid will flow from this opening and the player must place pipes on the grid to guide the liquid along them. Depending on the game version, the liquid may begin flowing after a certain amount of time has passed and you're still allowed to lay down pipe while it comes, other times the game gives you a time limit with which to lay down pipe, then sends the liquid down the path you made. You may also be required to guide the liquid along a certain minimum number of pipe segments, to guide it into a drainage tile, or both. Levels may also be pre-designed or randomly generated.
- Bonus Stage: You get one every few stages — depending on the version, it'll either by a Tetris-like level where you position blocks falling from the top of the screen to form your pipeline, or it'll be a sliding tile puzzle where you have to move around pre-laid segments to form a pipeline.
- Endless Game: Some versions of the game force the player just replay the final level over and over again until you eventually fail, others keep going with randomly generated levels.
- Luck-Based Mission: Levels with randomly generated designs can be either very friendly or very evil depending on how the Random Number God is feeling.
- Puzzle Game: Figure out how to create the longest pipe line you can within the time allotted to maximize your score on each level.
- Pipe Maze: Inevitably you'll end up creating something like this.
- Schmuck Bait: In some versions, the last two levels have only two empty spaces between the start and end pieces via a screen wraparound. The minimum distance is well over 20 though, so directly joining the terminators is a guaranteed Game Over.
- Scoring Points: The only way of tracking progress other than level progression, which in some versions is finite.
- Timed Mission: Not a direct example, but you have to race against the fluid flowing through the pipes as you lay them.
- Unwinnable by Design: In some variants of the game with randomly generated levels, it's possible to have your starting pipe section have the open end running directly into a block.
- Wrap Around: Some levels have holes in the side of the arena that transfer the fluid flow to the opposite side of the screen.