You can play the keyboard using 1 to 10, - and =. Mouse scrolling over works also. The object is to travel to all of the worlds spreading your musical talents. You will be rewarded with gifts of poetry. You also get to hear the song you created at the end of the levels :)
The LD theme was connected worlds. I took this two ways. The first was the obvious connecting planets through space flight. The second was more abstract connecting the worlds of music and poetry. Keep in mind, it was done in less than 48 hours, so the poetry especially is a little forced.
***I had to take out the save feature. It was resetting all of the planets for some reason.