New Quantro update that was just released today has two new ingame themes, two new menu tracks, new sounds and many new game modes - including competitive multiplayer. Listen to samples below for the music and check out the rest here at the Play Store.
Quantro is a free tetris-like game with innovative additions and twists to the classic formula, with new 3D game modes and rules, 36 unique falling pieces and multiplayer gameplay. It's great. Honestly.