Noobs: lvl 15 is easy, just let all the one's on the right hand side down by stopping them at the very bottom of the slope so they topple in the bottom right hole . Then all the ones from the left can go down at any speed. EASY.
Oh ,and another -1/5 for having to go through three menus to actually load a previous game, why not just not have a 'load' button next to 'start'. Down to 1/5