A showstopper stone on third level cannot be pushed, preventing further advancement. And sometimes when a stone is pushed and should fall down, a new stone is created and the original stone is pushed further...
You need to run from beginning to push it. But at level 7 glitch with invicible enemies and after starting from lvl 1 moving speeds up and it is good, but you see more space than level have, and some enemy also disappears
