Tetraminoes are pieces created from 4 blocks joined together into 7 different patterns. By rotating them, you can position the pieces as they are falling so they fill open spaces. When an entire horizontal line fills with the pieces, the line clears and you are on your way to higher levels!
Blocks will fall from the top of the screen towards the bottom. Arrange the pieces so that a row is completely filled by the blocks. Failing to do so will fill up the screen making it more and more difficult to clear rows. A cleared row will disappear giving you points and making game play easier.