You are the Conductor of an Electronic Symphony. Build defensive towers to keep the music from getting out of control. Each tower responds to a particular piece of the song, and the enemies spawn to the beat! You better think quick!
Yellow goes with the Melody,
Green kicks with the Bass,
Red zaps along with Strings and Synth,
Pink likes Claps and Snares,
Blue plays a shocking Piano/Chime/etc.
Also don't forget about the music attacks! Fermata, Szforzando Bomb, Decrescendo, and more!