You can unlock this achievement in easy mode, to activate it go into the main menu settings and look for the mode option. Here you have a choice between classic and easy. Chose easy and you unlock 3 stars at the end of each level. Please note if you enter the settings from the world map there is no such option.
After completing all levels you will have the achievement for using the time stopping ability left, because you can't use it without time counter. If you switch back to classic, you will notice you are back to level 1, because each mode have seperat progress. So you have to play classic mode until you unlock the time stopping abilty at level 23. Use it and you are done with the game.