I just completed this game.... not too bad.. a bit banal.. and for the monkey puzzle.. its actually NOT the rainbow, its primary colors, hence why the basic ones (blue, red and yellow) are fixed in place, you just have to make them collide with the color those two make when mixed in middle.. AKA red + blue= green, red + blue= purple and red and yellow= amber (orange) when they are all aligned a section should open...

Funny that, I did it the old wisdom style. Hear no evil, see no evil, speak no evil. Green, purple, amber.