This model was built as a TV version of the Hidden High-Zack.
The arms, legs, and waist were extended. The front skirt was enlarged. The chest ducts were replaced with plastic sheet louvers. The head was raised. The mouth ducts were extended and replaced with mobile pipes. The spike armor was sharpened with brass wire. The hand parts were replaced with Aspara Model parts. The verniers and thrusters were replaced with Wave parts. An original scope was added to the beam launcher.
These are the main modifications.
The paint job is a water-based hobby color, finished with a brush using the Shimizu method.

HG Hidden High-Zack | ガンバ's Gunpla works