shoop da woop
A combination of the above factors for me are mostly what make this game worth playing, the comic book strips in particular are great.
The arrow you could extend back and forth - it was hard to judge how much force you were going to throw a star with because the length you could stretch it was so short, it would be better to have a power bar where when you hold down the cursor the power goes up and you choose when to release. That also makes it easier to remember what your mistake was in your previous attempt. At the moment it is quite hard to judge how hard you threw the star in the previous attempt.
VERY IMPORTANT - Restart times being as short as possible! The time it takes to restart when you mess up is too long. In a game like this people often have to restart a level many, many times and that in itself is frustrating, but having to wait for multiple animations to happen every time you restart makes it far more frustrating. It should be practically instant.