|Developer(s)||Reddit user u/billdroman|
|Release||September 5, 2014|
|Playfield size||12 × 24|
Combinos is a falling block game similar to Tetris but uses all possible polyominoes from monominoes to decominoes.
Players can compete for a spot on the leaderboard. The top 10 players are shown, as well as how many games those ten players have played.
As the player progresses in the game, the game's randomizer uses more polyominoes from more difficult piece sets. The game starts with only the two easiest sets (tetrominoes and lower, and pentominoes), slowly adding hexominoes, heptominoes etc. as the game plays. Every 10 pieces dropped (starting with the 9th, then 19th, 29th, 39th etc), the randomizer gets a little bit harder, until it becomes effectively unplayable. There are a total of 12,678 possible pieces that can appear, in 29 different colours. Pieces with holes can be found in this game, as can I pieces of length up to 10. All possible I pieces have been seen, with the I1 through I7 appearing often. As of 8th February 2020, the I8 has four known sightings, whilst the I9 and I10 have only one each. The randomizer is believed to have 101 levels, with the indicator being a white line which goes down 1 pixel every level. The starting level is commonly referred to as Level -1, as the line starts 1 pixel above the level display. The reason that the actual highest level is unknown is due to the fact that nobody has ever gotten that far - the highest known level reached is 53.
A basic survival mode, the player's aim is to score as many points as possible by clearing lines, especially combo line clears. The scoring system is , where L is the number of lines and C is the combo. Due to this, a good enough combo can be worth a huge amount of points, making 4-wide one of the most common starting strategies despite it being unreliable due to the randomizer. The current high score is 770, set by Uni99.
In battle mode, two players compete. Clearing lines will increase the size of the opponent's next piece.
Up to 5 players can play race mode.
Combinos uses a unique rotation system. Each piece has its own specified "maximum kick distance", which determines which kicks the game will attempt before considering the rotation to be impossible. A piece kick distance of 0 cannot kick at all, whilst a kick distance of 1 means the game will try 8 different kicks (left, right, down, down-left, down-right, up, up-left and up-right, in that order). If a piece has a kick distance of 2, extra kicks are added, but the exact details are currently unknown. It is believed that these extra kicks are only in one direction (up, down, left or right), and the direction it attempts is based on where the collisions are on the original rotation, although this has not been confirmed and is likely incorrect. The highest kick distance is 5, which only the I10 piece has. Curiously, the X5 piece, despite having a rotational symmetry of 4, has a kick distance of 1, instead of 0 (however the O4 has a kick distance of 0). This trait is shared with various other pieces with a rotational symmetry of 4, such as the "Donut 8" octomino and the 3x3 square nonomino.