|I cleared all of the gems in island 3... the one with the broken bridge and dogs was incredibly frustrating. There was also the Cortex Power level with multiple split paths, and I had to memorize which paths had boxes in it... |
The Heavy Machinery level was the easiest gem to get so far. I also did the N. Brio bonus round here... I don't remember if I did the bonus round in Slippery Climb already or not...
Then I did one of the gems in island 2 which was a cakewalk even compared to Heavy Machinery. The level with the boulder chasing after you... it actually has an alternate exit where a bunch of boxes are hidden, only accessible with a colored gem.
It's possible I might finish the gem and bonus rounds next time I play this.. but then again the difficulty in this game is all over the place, so who knows.