Blunder Jaw is the final boss and the main antagonist of the game Astro's Playroom. It is encountered in the 1994 Throwback after activating the Tech Demo. It is based on the first tech demo for the PlayStation 1. Its boss fight is split into two parts; battling the CRT-Rex, and battling the 4K-Rex.
Appearance[]
As the CRT-Rex has the appearance of a standard, somewhat low-quality depiction of a tyrannosaurus rex, with brown scales and yellow eyes. However, as Blunder Jaw, it becomes mechanical in appearance, changing from brown scales to green metal, and its eyes becoming white with red pupils. Additionally, the inside of its mouth contains a red device that can be used as a flamethrower, situated above its tongue. It also gains hairs on its head, and spikes down its back.
History[]

The original tech demo. Demo 1 T-Rex.
The T-Rex was created as a tech demo to showcase how models would appear on a PlayStation 1 screen.
Astro's Playroom[]
After activating the Tech Demo in the 1994 Throwback, a stairway of Memory Cards and some discs appear out of the abyss, and Astro Bot climbs them to a gray platform. After the checkpoint on the platform is activated, Astro proceeds forward, and the screen narrows as the CRT-Rex approaches. The battle begins as soon as it roars at Astro Bot.
CRT-Rex[]
The CRT-Rex has multiple attacks that appear during this phase:
- It roars and multiple Knockers are thrown from its mouth.
- It roars, and three discs fly in an arc at Astro Bot, which can be dodged by jumping over them or moving out of the way.
- A section of the platform is highlighted, and the CRT-Rex bites down on the highlighted part. This happens 2-4 times. Its teeth glow yellow for a second to signify the final bite, and when it bites, a small wall of flames moves to the left and right of the teeth, which must be jumped over.
- Eventually, the former attack is extended to have the CRT-Rex tilt the platform while biting down, with walls of fire moving down the slope. Sometimes, the CRT-Rex gets tired after the attack, and is stunned momentarily after, allowing Astro Bot to hit it in the eye. Once it is hit in both eyes, it falls into the abyss below, and Astro Bot does a victory dance, but the CRT-Rex, now mechanical and known as the 4K-Rex, appears and roars, causing Astro Bot to fall down and causing the scenery to change to a stormy ocean.
4K-Rex[]
This phase has a short platforming section which rises out of the water, requiring Astro Bot to platform while the 4K-Rex breathes fire continuously, causing the platforms to break. Eventually, Astro Bot reaches a second gray platform, and the 4K-Rex attacks with different attacks here than as the CRT-Rex, those being:
- It prepares to fire multiple lasers out of its left eye, which show where they hit before they fire.
- It fires many small meteors toward the platform in a random pattern, which highlight the ground in a pixelated circle, showing where they hit.
- Like the last phase, it bites down on the platform. However, this time, the attack hits more of the platform each time, and the last one does not fire a wall of flames.
- It roars and multiple Knocker and Jab-Jabs fly out of its mouth.
- It fires five discs at Astro, two at once and three after. They have a different pattern than as the CRT-Rex and are faster.
- After a while, it starts the laser attack again. However, the third one destroys a section of the platform, revealing a gold trophy underneath. Astro Bot must throw this trophy into its eye, causing it to be stunned and allowing Astro to punch it in the eye multiple times, damaging it and destroying the targeted eyeball. The second time it uses the attack, the lasers are faster, and it fires five lasers, the final one revealing a platinum trophy.
Once both of its eyes are attacked, it rests its head on the platform, and sticks out its tongue. Astro Bot must pull the tongue away from its body, and eventually, the tongue snaps back and hits the 4K-Rex in the face. The 4K-Rex falls into the water while breathing fire upwards, leaving its fate unknown.
Trivia[]
- The trophy earned for unlocking the PlayStation 5 is a reference to the PlayStation motto (Play Has No Limits).
- The boss Mighty Chewy shares much of its move set with this boss in Astro Bot.
- A similar creature to the 4K-Rex appears in the level Machine Learning of Astro Bot named Blunderjaw.
- The T-Rex Roars are the ones from Jurassic Park