Stuck in level 113, any hints?

The main objective in 113 is to clear the bubble, although first you need to get rid of the rocks blocking the path. This one may take a few tries and a little luck but the best way is to focus on making rockets (and other boosters if possible) to let you clear the rocks as soon as you can.

Check the video below for a completed run on this level and keep trying until you get lucky with a few more boosters.