Octaves, drag left or right to go up and down octaves
Faster spawn/speed of asteroids
Less hp and damage of asteroids
Faster note-bullet fire rate (still works on recording the song)
Chance to half a free ride between planets (i.e. can play a song or skip it)
A chance to fight a miniboss ship (the chance goes up at higher difficulty planets)
New launch animation
New turret deployment animation at the start of a stage
New meteor graphics
UPDATE 10/8/2014: I am working on new content for the demo. It should be published soon.
UPDATE 8/26/14: By request, I added a free piano mode. Careful, the massive spam of notes that you can produce will cause lag. Also, you can play more like a piano now with alternate keys. 1 through = still works, but s through k and e, r, y, u, i will provide for a more realistic piano feeling.
UPDATE: Added a hard mode. I would suggest flying around easy areas to get some reinforcement before moving to last sections.
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.