1989 game built by Atari. Coloured tiles tumble down from above; you have to catch them on your paddle and drop them into a 5×5 bin. They vanish when you line up three or more of the same colour, a feat referred to as a "Klax". The paddle can hold up to five tiles.
The game is 100 levels ("waves") in length, giving the player the opportunity to skip five or 10 of them every five levels, but never allowing you to skip past the 91st stage. So a minimum start-to-finish playthrough is 40 levels long. To pass a level, you have to meet its requirements in order in (almost) each set of five waves: make a number of Klaxes, make a number of diagonal Klaxes, achieve a certain score, survive a set number of tiles, and make a number of horizontal Klaxes. You lose if you fail to catch a certain number of tiles (three, four or five, depending on how far you warped at your last chance) during a set of five waves, or if you fill the bin entirely without clearing enough tiles.
Klax provides examples of:
- Big "YES!": The female announcer does this when you score a combo.
- Catchphrase: Many, given by the voice synthesizer.
- Critical Existence Failure: All is well until you drop that last tile and then: "Awwwwwww"
- Difficulty by Acceleration: As the stage continues, the pieces become more dense requiring faster reaction time. Sometimes, you also receive that wonderful hint: "This one is fast!" - the game is not kidding.
- Hint System: A hint is displayed on the objective screen before each wave.
- Hold the Line: The survival waves, where you must catch a certain number of tiles to win.
- Nothing Is Scarier: With regard to the arcade version's complete lack of soundtrack. Some nice, soothing background Muzak would be well placed, but no, all you get is the relentless clack, clack, clack...
- One-Word Title: Named after the sound of rolling tiles.
- Palette Swap: All the tiles, except in the Game Boy version.
- Path of Most Resistance: While you get a nice bonus, extra leeway on dropping tiles, and you skip the intervening levels when you warp, you can get a far higher score playing through every single level.
- Sound-Coded for Your Convenience: In the arcade version, each colour of tile produced their own unique sound effect as they tumbled. Also, there are three different versions of the four-note jingle that plays when you score a vertical, horizontal, or diagonal KLAX.
- Speed Metal: The NES port's soundtrack by BügSük (Lx Rudis and Dave O'Riva).
- Studio Audience: One of the few video games (arcade or otherwise) to try to emulate this trope. The audience claps when the player clears a wave, and groans when the player gets a Game Over.
- Suspicious Video-Game Generosity: Whenever a stage's hint says "This one is fast!", whatever quota you're meant to meet is notably lower than it normally is for the point in the game you're at. There is a reason for this.
- A Winner Is You: A little congratulatory sentence and a bonus 1,000,000 points.