Sonic Eraser

A falling block puzzle video game, it became available for download in Japan in 1991 and in Brazil in 1995 on Sega Meganet, a Japan-exclusive Sega Mega Drive add-on released in 1990 and later released in Brazil in 1995 that enabled players to download a select library of games via dial-up internet. Sonic the Hedgehog, controlled by the player, must arrange randomly selected falling clusters of shapes of the same variety to align on a grid to erase them. The falling shapes used in gameplay include a red tetrahedron, a pink cross, a green gemstone, an orange octahedron, a white gemstone, a yellow tetrahedron and a blue sphere. The general aim for all game-modes is to align two or more of identical shapes in any fashion if they lie adjacent to each other inside a 13x7 grid. When this happens, the shapes disappear, give the player a sum of points to add to their score, and subsequently make empty space on the grid for other shapes. 

The erasure of some shapes may cause other shapes on top of it to gravitate directly downwards in their column. If the fallen shapes also align with other shapes, it causes a chain reaction, giving the player more points. Inevitably, the grid will become filled with shapes, and when the shapes hit the top row of the grid, the game is over. The game also has two boxes labelled 'Next', which show the shape cluster being deployed after the one currently falling. The game also features multiple modes, those being a competitive two-player mode, a single-player mode against a computer, and a two-player cooperative mode. In the versus mode, players can attack each other like in Puyo Puyo. In the two-player co-op mode, there are four game types: 'Round', 'Normal', 'Doubt' and 'Block'.