what does "needs more power" do I did all the blue shells but nothing i ended up finishing the map with buyable

1.inside launch pipe 2.on top of launch pipe exit 3.on top of upper right corner of large waluigi sign 4. under right side of the bottom most star on the waluigi sign in corner behind ball rail 5.left side of waluigi sign bottom most star 6. under the HAMR jump on the death pipe 7. on the left star of the small pinball sign 8. in the right corner under the rack were deadshot sits 9. on top of right palm tree of the large waluigi display 10. on top of the ceilling on a pipe heading towards spawn

Does the ds give something? Nothing seen, or missing some idk? Btw get all blue shells, there are more, and 2 in the big field. Get the 4 new shells in mystery ? mario boxes in big field. Pack a punch tool in in corner at the end? WHAT DO DS do?