Fourth wall

Sometimes a character in the Crash series will do something that acknowledges that they are inside a video game; this can be things such as stating the title of a game, mentioning a game mechanic in a way that makes no sense in-universe, looking right at the camera, or other things that acknowledge our reality. This is called a fourth wall break, and things like this have happened several times in the series.

Crash Bandicoot
In the first level, when Crash gets up after washing up on the shore, he grins at the camera and gives a thumbs-up before turning around.

Before Crash hops on a hog in hog riding levels, he turns around, looks at the camera and wiggles his eyebrows.

Crash Bandicoot 2: Cortex Strikes Back
Like the previous game, Crash wiggles his eyebrows and looks at the camera before hopping on Polar in Polar's levels (with the exception of Un-Bearable.)

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

Crash Bandicoot: The Wrath of Cortex
Upon playing two of Wa-Wa's levels, he will tell the player to "Leave my levels alone!"

Crash Bandicoot: The Huge Adventure
One of Crash's idle animations features him pulling a Gameboy Advance, the console that the game is on, out of his pocket, looking at the camera for a second, then briefly playing with it before putting it back.

Crash Nitro Kart
If the player sits idle for a while when playing as Cortex, he will look over his shoulder and motion with his hand at the player to get moving.

During gameplay, Coco can sometimes be heard humming the game's theme tune.

Crash Twinsanity
One of Crash's idle animations features him turning to the camera in a fighting stance, throwing a few punches in the player's direction. Some other idles have him peeking over his shoulder at the player when facing away.

The last skunk seen in Jungle Bungle expresses his displeasure at having acted as a common enemy to get stomped on for ten years (despite the first Crash game having been released 8 years before Twinsanity): "Hey, hey, hey! Yeah, you! I've been doing this, for ten stinkin' years! Back and forward... back and forward... AND I'M SICK OF IT! Well I'm not gonna do it no more!"

When Farmer Ernest promises a crystal in return for ridding his orchard of worms, Cortex just shoots him and takes the crystal from him. He then looks at the player and says: "I'm an evil scientist, what did you expect? This isn't a game."

Cortex mentions to the penguins in Ice Climb that the reason he couldn't pay them was because "Wrath of Cortex didn't do as well as we'd hoped."

Just as Cortex, Crash and Nina jump into the 10th Dimension, Cortex references the game's rushed development by saying: "Come now, as we explore a new dimension! ...It should've been two new dimensions but we... ran out of time."

At the beginning of Rockslide Rumble, Evil Crash with Nina jumps over a railing as Cortex runs up to it and exclaims "My daughte- errr... niece!" This references confusion developers had over how Nina was related to Cortex.

At the ending of the game, when the Evil Twins are about to be eaten by Evil Crash, Victor turns to Moritz and says: "Well, this is one heck of an ending."

A cut section of a voice line has Cortex instructing Crash to "Hit spin and then circle to throw me over there.". The "spin and then circle" part was removed since it only made sense on the PS2 version, thus removing the fourth wall breach.

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-Rama Cold Lunch, he looks at the camera and shrugs his shoulders.

Sometimes, Crash waves at the camera and even smiles 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 by saying ''"Excuse me gamer, are you trying to make me lose?!" ''Another of Cortex's lines says, "I would have hit him, but this game is rated E."

There are also some fourth-wall-breaking moments with the mission hints that are given if the player talks to a mission character without the required item or with insufficient Wumpa Coins/Power Crystals. For example, talking to someone who needs Crystals four times will prompt the message, "Just play the game, OK? Jeez.", or talking to N. Gin without the Slippers he needs will eventually prompt the messages, "You know what? I'm out." and "Seriously, forget this, I'm going to make accounting software."

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 Crash Tag Team Racing, in which he did not appear.

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

Uka Uka prolongs a cutscene so he can enjoy the dramatic background music.

The Voodoo Bunnies are discussing Uka Uka's personality issues, saying that he's feeling self-conscious about not having a body, and mentioning that "He had body briefly in Twinsanity, but that was no fun for nobody," mentioning Uka Uka's boss fight possibly meaning how short it was in said game.

It's possible that Ratnicians broke the fourth wall about saying two well known video game characters (Mario and Sonic).

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!"

Like the prequel, Ratnicians possibly broke the fourth wall about saying two well known video game characters.

Crash Bandicoot N. Sane Trilogy
In all three games, before hopping onto an animal, Crash or Coco will look toward the camera, as done in the original counterparts. However while Crash still wiggles his eyebrows, Coco winks at the player.

In several instances, Coco shows irritation at the player, glaring right at the camera. There are multiple ways to trigger this:
 * When Coco misses 30 or more boxes in the first game.
 * When Coco hits an explosive object on the jet-ski levels.
 * As an idle animation on any on-foot platforming level in all three games.

One of Coco's idle animations has her browsing r/CrashBandicoot on her laptop, a real-life fan run Crash Bandicoot community on the website Reddit.

Crash Team Racing Nitro-Fueled
When the player beats all of N. Tropy's ghosts in time trial mode he will talk directly to the player and say that they have earned the right to choose him in the character select screen.

In one of Ripper Roo's idle animations, he will turn his head around to briefly stare at the player before laughing and turning back forward.

Spyro has a similar idle animation where he glances over his shoulder at the camera, mimicking an idle animation from the original trilogy of his native series.

Crash Bandicoot 4: It's About Time
In the official trailer, Lani-Loli asks Crash and Coco how many times they beaten Cortex. Coco replies with "Three," making Lani-Loli confusedly lament that it had seemed like more times than that. This lampshades how the game takes place on an alternate timeline, just after Warped.