Here's the list of the most important changes:

-Added 2 adventure stories.
-Added CO-OP adventure mode.
-New unlockable character: Tyler Coats.
-New item: Guitar Tuner.
-Added achievements support.
-Added unlockable HD versions of some songs.
-Added rythm helper option.
-Other minor fixes.

You can give us some feedbacks under this post.
We will take every suggestion into consideration.

New updates are coming very soon.