Hey! ^^
Finally! XD It took some time to make this picture complete~
It's easier to understand the point, if you've played Crash Bandicoot 2: Cortex Strikes Back. 8D
My fave level is The Eel Deal, and the other sewer levels~ =]
I think the levels have some funny names. XD
Here're some illustrations of, how to get the Gems in the game! ^^
Hope you like~

Old Crash Bandicoot(c) - By Naughty Dog
Art(c) - By me
Turtle Woods: I wanted to show my sister that I could go through an entire level without breaking any crates, and then I was shocked when a huge blue gem appeared at the end of it all!
The Eel Deal: Very, VERY carefully...
Bee-Having: I wanted to jump on the staircase, so I went to the end of the level, hit the Nitro Crate Exploder, and then came back, but the crates hadn't exploded and that was when I realised that they weren't moving, so...Leap Of Faith Time! In the Beta Version, the Nitro Crates are real, but one of Crash's attacks can destroy them without him dying...
yellow is hardest gem of five gem's urgh!
rest of gem's bweteen blue and yellow fun and balanced
and if possble maybe someday i want that series as HD trilogy! to PS3!