Fourth wall

Sometimes a character in the Crash series will state an actual Crash game, or look at the player, which is called a fourth wall breakthrough, and this has happened several times in the series.

Crash Bandicoot
Before Crash hops on a hog in hog levels, he turns around and looks at the player and raises his eyebrows up and down.

Crash Bandicoot 2: Cortex Strikes Back
Like the previous game, Crash raises his eyebrows up and down and looks at the player before hopping on Polar in Polar's levels.

Crash Bandicoot 3: Warped
When Crash is smacked with a Two-Headed Giant's club in Double Header, Crash will hit the screen and slide down.

Crash Twinsanity
Cortex mentions to the penguins at one point "The Wrath of Cortex didn't do as well as we'd hoped and--".

Cortex blasts Farmer Ernest gaining the crystal he had he then looks at the player and says "I'm an evil scientist, what do you expect? This isn't a game."

Crash Tag Team Racing
Von Clutch mentions that he has all of Crash's Games and that they are his favorite video game heroes.

When the yeti eats Crash in the Die-O-RamaCold Lunc, he looks at the camera and shrugs his shoulders.

Crash waves at the camera in certain Die-O-Ramas.

Crash smiles at the camera in some Die-O-Ramas.

Cortex will ask the player if they're trying to make him lose if the car keeps crashing or skidding into walls.

Crash of the Titans
Cortex mentions that his name is on the stationary, referring to Radical Entertainment, he also pulls out a contract.

Tiny says to Crash "I'm still mad about the last game" referring to CTTR, which he did not appear in.

In the DS version, Tiny says "Cool, maybe Ill get my own series now" if the player dies during his boss battle.

One of the Voodoo Bunnies mention Crash Twinsanity, and Uka-Uka's boss fight in it.

Crash: Mind Over Mutant
N. Brio yells out in a cutscene "I, was in the First GAME!!".

One of the Slap-Es says "Curse you video games!".