Hebereke's Popoon (へべれけのぽぷーん Hebereke no Popūn) is a two player puzzle based on the Hebereke series. Hebereke means drunk or untrustworthy. Popoon is an onomatopoeia for the sound made by the game pieces when they explode.
Hebereke's Popoon is a block-grouping game closer in style to Dr. Mario than Tetris. There are eight playable characters, each having different abilities. In one-player mode, the player is forced to choose Hebereke and must play against Oh-Chan. After defeating Oh-Chan, the player is allowed to choose between Hebereke and Oh-Chan in the next match against Sukezaemon, and so on, until the player has "unlocked" all the characters. Each match consists of a single-round. A defeated player may elect to resume play by using a continue. In two-player mode, all characters are immediately available to either player and each match is the best of three rounds. Players can also select a handicap level (from 1 - 5) to increase or decrease the difficulty of the game.
In each round, pairs of Popoons of various colors (the set of colors varying with the character(s) chosen by the player(s)) descend from the top of the screen. These can be rotated and placed by the player. The immediate aim is to create groups of three blocks of the same color arranged either horizontally, vertically, or diagonally. When such a group is created, the member blobs blow up, disappearing from the screen. Any blobs above the disappearing group then drop to fill any resulting empty space.
Each time a player successfully creates a group, a piece resembling the head of the player's character will drop on the other player's screen in a random position. These "heads" can be removed by the second player by placing a blob of the same color as the head such that it touches the head either horizontally or vertically. Both the head and the blob will disappear from the screen, in much the same manner as group of blobs, though no head will appear on the first player's screen as a result.
A player can sometimes cause multiple groups to disappear. This can happen simultaneously if the placement of a pair of blobs immediately causes two groups of blobs (or heads) to form or it can happen in a chain reaction, as the formation and disappearance of one group causes the dropping of any pieces above it, which can result in the formation of another group, and so on. If the groups in either process are of different colors then this is said to be a combination or "combo." The colors in a combo (or even a group) appear as small tiles in the lower of two panes in the middle of the screen and above the score-box.
While a combo of one color (simply an ordinary group) causes a single head to appear on the opponent's screen, a combo of two colors causes a full row of heads to appear on the opponent's screen. Combos of three and four colors are much more dramatic, the precise effect depending on the player's character. Upcoming heads or special effects are kept track of by symbols placed by the players' characters in the upper of two panels in the middle of the screen.
A notable feature in Hebereke's Popoon is the constant bevy of sound effects as each player's character celebrates each group or combo by making nonsense sounds or yelling Japanese phrases.
Source: Wikipedia, "Hebereke no Popoon", available under the CC-BY-SA License.