Hope you continue on it. Each world has 5 to 8 galaxies, and there are 6 Worlds. Maybe you should remove the Grand Star thing (where you place the stars) and place them in fortresses. Also, in the original version, if you're aiming for 100%, you should end up with 121 Stars. So good luck on clearing these goals! (Look up Mario wiki for list of galaxies)
But remember, I'm pretty sure there aren't 121 galaxies, there are just different stars for each galaxies, for example the comets etc.