Impossible 10 is a logic-puzzle, tile-merging game played on a 5x5 board. The player's goal is to earn points and merge numbers until they create a number 10 tile. Once they reach this goal, they receive bonus points. Their new goal is to then beat their last-best score and continue to merge tiles until they reach 10 again.
The player can only match identical adjacent tiles. Unlike similar games, merged tiles don't create a new numbered tile via mathematical addition. Instead, the tiles merge to create the next-highest number. The player can also merge more than two identical tiles at a time. For example, if the player merges three number 2 tiles, they don't create a number 6 tile. They create a number 3 tile.
Impossible 10 helps the player match tiles by making each tile with a different number a different color. The player must also make a double selection, which helps them prevent mistakes. For example, if they select a group of adjacent tiles, the game highlights those tiles by forming a line-frame box around the number on each tile. The player must select the group again to merge the tiles.
The game always forms a new tile in the position of the last selection on the board. If the player makes the right selection, they can position the new tile next to a matching one. For example, if the player plans to create a 3 tile using 2 tiles already positioned next to a 3 tile, they should select the 2 tile closest to the existing 3 tile to merge all tiles at that position on the board.