Colored Beans (Puyos) fall in pairs from the top of the screen. You can control their descent with the D-pad and rotate their formation with the action buttons. The object is to match colored sets of Beans into groups of four. When four Beans of a like color connect, they disappear from the playfield, causing all the Beans stacked on top to drop a level which can cause chain reactions for big points. The Beans come in 5 different colors: red, yellow, green, purple, and blue (though you won't have to deal with blue ones until the mid levels) and fall progressively faster as you work your way up. The drop rate will occasionally increase even in the early stages, but these bursts are only temporary.

   Scenario Mode (Hitori de Puyo Puyo) is the basic 1-player arcade mode. The goal here is to work your way through a series of 13 increasingly difficult opponents. Both you and your rival have a pit for falling Beans, and the first to let theirs get filled to the top loses. In the early stages, it's possible to win by simply playing on the defensive and making sure your pit stays as empty as possible. As your opponents become increasingly sneaky, however, you need to strategically stack your Beans so as to cause chain reactions, which send Refugees (Ojama) cascading into your rival's bin. Refugees are transparent beans dumped at random to muddle the plans of their unfortunate recipient. They can't be connected like normal Beans and can only be eliminated by having them touch a cluster of disappearing colored Beans. The amount of Refugees dumped depends on the length of the combo that created them, hence the importance of planning large chain reactions.

   Scenario Mode consists of 13 opponents, all pulled from DiC's low-budget "The Adventures of Sonic the Hedgehog" cartoon show: Arms, Frankly, Humpty, Coconuts, Davy Sprocket, Skweel, Dynamight, Grounder, Spike, Sir Ffuzzy-Logik, Dragon Breath, Scratch, and of course Dr. Robotnik himself. (Though all of these characters appeared at some point or other during the cartoon's run, only Coconuts, Grounder, Scratch, and Robotnik were regular cast. Coconuts and Grounder are loosely based on Sonic 2's Ai-ai and Handrill enemies, called "Coconuts" and "Grounder" in the English manuals.) Each opponent will take a moment to indulge in some trash talk before the round begins and it is foul punnery of the lowest denomination which you can thankfully skip through.

   In addition to the 1-player Scenario Mode, there's a 1P vs. 2P Mode (Futari de Puyo Puyo) and an Excercise Mode (Tokoton Puyo Puyo). Excercise mode is a low-pressure 1-player game with no opponents. The only object is to last for as long as you can while racking up a high score. If you've been performing fairly well, but your situation has nonetheless turned bleak, you may be blessed with a visit from Big Bean (Big Puyo) or Has Bean (Carbuncle, the Puyo Puyo mascot). Big Bean falls through the bottom of the screen in a straight vertical line, eliminating the two rows of beans that stand in his way. He should be used cautiously, because if the fat green turd cuts through any potential chains, he'll do more damage than good. The more frolicksome Has Bean trots in a random, winding pattern through your crowded bin, converting all of the Beans he touches to one color. (Big Bean and Has Bean do not appear in Scenario or versus modes.)

   In the Options menu, you can adjust the default button layout, choose the computer difficulty level (easy, normal, hard, or hardest), set the 2-player match count (1, 3, 5, 7, 9, 11, 13, or 15), toggle the "sampling" on or off (refers to certain sound effects), or mess with the input test to make sure all the buttons on your controller are in working order.

In December of 1989, when the MSX computer platform was enjoying its heyday in Japan, Compile released "Disc Station Special #5 - Christmas," the fifth in a series of supplements for their popular Disc Station disk magazine. Among the playable minigames in the issue was a comical dungeon RPG called Madou Monogatari. Its popularity was such that, just six months later, Compile released Madou Monogatari 1-2-3, a stand-alone title featuring a graphically enhanced version of the original game along with a prequel (Madou Monogatari 1) and a sequel (Madou Monogatari 3). Compile had a hit on their hands, and the cast of the Madou games continued making cameos in further issues of Disc Station.    In October, 1991, Compile released a Tetris-style puzzle game featuring Puyos, the generic "slime" enemies of the Madou series. Puyo Puyo, as the game was called, featured only the basic Tokoton mode (no computer opponents to play against), and had blobs of six colors: red, yellow, blue, dark green, light green, and gray. The game was released exclusively for the MSX2 and Famicom Disk System platforms and so only reached a limited audience until the arcade version was released in October of the following year. This is where Sega's involvement in the series began, as the game was developed on Sega's C-2 board. This version introduced the 1-player competition mode by having Madou Monogatari star Arle Nadja face off against other members of the Madou cast. The game's popularity exploded and the Puyo series would become Compile's bread and butter for the next decade.

   On October 18, 1992, Sega released a near arcade-perfect port for the Mega Drive. The company was interested in distributing the game in the US and Europe, but feared the distinctly Japanese stylings would alienate Western players. In response, they jettisoned the Madou theme completely and re-outfitted the game with a Sonic motif, specifically, that of "The Adventures of Sonic the Hedgehog" cartoon show, which had recently begun airing in the states. The subsequently titled Dr. Robotnik's Mean Bean Machine was released in the US and Europe in November of 1993. (Incidentally, the game was also ported to the Super Famicom as Super Puyo Puyo, which underwent a similar restructuring for its US release, Kirby's Avalanche.)

   In addition to the obvious cosmetic changes, Mean Bean Machine also introduces a password feature which is not present in the original Japanese Puyo. (The original version actually allows you to start from stage 1 or 4, and also includes a 3-stage training mode.) The silly banter of the Madou cast that precedes each round, while not exactly high entertainment, is still a cut above the awful smack talk of Robotnik's cronies. Other than some narrative devolution, however, the two games are basically identical. Here are some screenshots from the Japanese Mega Drive version:

   Compile, incidentally, filed bankruptcy in 2002, after which Sega gained total ownership of the Puyo franchise. Sonic Team's Puyo Puyo Fever became the first title released under the new regime.