The objective of PiCOPiCT is to move coloured blocks from the bottom of the touch screen under falling blocks of corresponding colors. If a shape is made using the added block, the blocks add to an image on the top screen. For example, if players form a red block sequence, the image will gain as many red blocks as has been cleared, assuming that the any blocks of that colour remain to be added. If blocks fall as a result of clearing blocks that were attached to it, they are added to the blocks at the bottom and can be used, though a special variety of block exists that cannot be picked up, forcing players to either clear them before they land or wait for the right blocks to fall on them. As players clear more blocks, they will eventually form an image. These images are of 8-bit renditions of characters from NES games, such as Mario, Link, and Bowser.
Players' performances are judged on two qualities - their score and their time taken to complete a level. A high score is often achieved by comboing clears, a task accomplished by either clearing blocks before a clear from before has finished, or having blocks fall and form a clear as a result of a previous clear. On the side of the touch screen is an item called a "POW Block", which players may use to clear the bottom two lines and drop all midair blocks, but sacrifices a reserve space with each use. Coins earned in the stage can be used to regain the lost reserve spaces. There is a more difficult version of each stage called "Ura", "Dark" or "Remix". These stages are locked initially, and can only become playable by using coins, which are achieved by clearing certain kinds of blocks. These coins can also be used to purchase songs that appear in the in-game store; the initial purchase includes only the original version of the song, while the remixed version can be purchased for an increased price. These songs can also be listened to while the Nintendo DSi is closed.