Piston It Away

Piston It Away is the twenty-first level in Crash Bandicoot 2: Cortex Strikes Back. A futuristic level set in Dr. Cortex's professional science factory, it requires Crash to avoid giant pistons, nefarious shrink rays, Sparky Tentaclebot Units, and Glowing-Hot Hoop Skirt Sexbot Units to survive.

Obtaining the Clear Gem for breaking all 69 crates is one of the most difficult tasks in the game, because ludicrous backtracking is the order of the day. This level contains a terrifying Death Route, but if the player takes it and finishes it right when they first encounter it, they will miss out on a number of crates past it on the main path. Instead, they are expected to take the main path to the end first - leaving one Sparky Tentaclebot alive so that they will be able to successfully backtrack all the way through the level to the Death Route. From here, all that separates the player from their rewards - the Death Route Gem and, if they didn't screw anything up, the Crate Gem - is a series of tricky platforming challenges involving awkwardly placed pistons, awkwardly placed shrink rays, and conveniently placed floating Sparky Tentaclebot Units. (Interestingly, even this level's Bonus Round embodies this spirit of backtracking, requiring the player to leave enough boxes intact to allow them to backtrack after activating a ! Crate.)

Trivia

 * Interestingly, when Crash gets shrunk by one of these shrink rays, he doesn't die immediately, but is instead briefly still playable while in the process of shrinking. As such, it is fully possible to complete the level while shrinking, and survive the shrinkage, though this absolutely cannot be done.