Crash Bandicoot 2: Cortex Strikes Back Tips

Coloured Gems
BLUE: Go to Level 1, Turtle Woods. Instead of breaking all the boxes, don't break ANY boxes. At the end, get your blue gem.
RED: Go to Level 7, Air Crash. At the first jet ski, jump across the boxes to the platform. You will be transprted to a secret part of Level 2, Snow Go. Make it to the end of this path and snag your red gem.
GREEN: Go to Level 10, The Eel Deal. At the first fork, go right. You will see an area littered with Nitro. At the end, jump through the wall (yes, you can do it) near the Nitro in an L shape. Make it to the end and grab your green gem.
YELLOW: Go to Level 11, Plant Food. If you break the first checkpoint at the right time, a timer will start. Make it to the end without dying or breaking open any more checkpoints under the designated time and recieve your yellow gem.
PURPLE: Go to Level 20, Bee-having. About 1/2 through the level is some Nitro in the shape of stairs. Go ahead and jump on them, they won't explode, as they are fakes. Climb to the top. You will be transported to a secret part of the level where the purple gem waits for you.