Hi Katja,
I just replayed the levels. Here's what I came up with:
W10L2:
Begin by pushing the boulder marked in purple counter-clockwise. Follow it around and push the other boulders counter-clockwise as well. This results in a boulder placed at the blue X. Once in the center. Use the metal boxes to guide the boulder to where you want it.
W10L3:
Place the reflectors as shown. Place Stinky on the purple X and make the UFO fire two shots. That leaves you with plenty of boxes to put one at the yellow X and collect the bonus coins.
Let me know if you need further help, I'll be happy to give it to you.
Mette
