Great idea :), really started to get into this one :).
Small bug, in that at 0/5 yellow squares collected, the text is to high, and as soon as you collect one, it drops down to a normal place (no idea how that occurs).
Not sure if you wanted the square to be able to rotate, looked fun when it was spinning madly :), but otherwise might need to freeze rotation on Rigidbody.
I Enjoyed the music, fitted in well with the look and feel.
great job, well done! :)