There are only a few things left you need to do to achieve this.Get to the final stage to finish the last two challenges on the top.Remember to knock the bell to get collectibles.Then finish the final stage on S rank and get the last two red stars.You need to get one of the stars using the rocket ability.<br />
After completing this sort of things, go to shop and buy some skills.<br />
I think you can get some other chievos first such as finish a challenge I've finished to get the "half of the challenges" chievo.I hope I made myself clear.<br />
P.S Dont forget to complete some stages on S rank before using this save because some chievos may pop out of order<br />
Glad I could help.