Hi!
I'm completley stumped on this level... It's the one with the three wheels on top of each other, where the yellow sticky ball is introduced. I can build a structure that takes me up on the first two wheels using the froggie goos and the yellow goo, and gather up the two skull goos on the way up. I cannot get past the third wheel however...

I've found out the skull goos are the only ones able to survive contact with that wheel and it does seem they have some sort of adhesive force there since they stick to it, but only weakly. I release the yellow goo from the middle wheel once the frame are on top of it and the skulls have a chance to stick to the top wheel. I've tried minimizing the size of the frame so its only the basic gray square you start with they'll have to lift (with all the other goos running around on it), but even with both skulls touching the deadly wheel they can't get enough force to lift the other goos upwards. The yellow goo dies on contact with the wheel so that's not it.

This level has been bugging me since yesterday evening and I can't proceed without beating it. Please give me some hints, it's driving me bananas that I can't solve it =)

Just stick the yellow goo to the little platforms with no spikes on them on the wheel.  ;)

Awwww!! I just knew it would be one of those forehead-slap-silly little things I'd missed... Worked fine, but I would never have guessed it myself, couldn't see that those things sticking out were special from the rest of the wheel. Thank you very much, I can now move forward with my weekend ;)

Hey Thanks MacAttack!