LTris as a tetris clone which means you have a bowl with blocks falling down. By rotating and moving the blocks you try to assemble whole lines which then disappear. LTris has three modes for this: Classic is the classical one where you play until the bowl becomes filled, Figures resets the bowl contents to a new figure for each level and adds suddenly appearing tiles and lines later on and Multiplayer where up to three players either controlled by human or CPU(!) compete and send completed lines to each other.
Even if you don't like Tetris you can download it, just to see your CPU in action in mode Demo.