GHZ meaning in General ?

Green Hill Zone or simply Green Hill is the first level of the platform game Sonic the Hedgehog, which released for the Sega Genesis in 1991. The level is grassy and lush, with environmental features such as palm trees, vertical loops and cliffs, and is the home of numerous forest animals. Like the game's other levels, Green Hill comprises 3 acts; in the third, Sonic fights antagonist Robotnik before moving to the second level, Marble Zone. It was constructed by level designer Hirokazu Yasuhara and its musical theme was created by Masato Nakamura.

Green Hill Zone is considered to be a classic within both the Sonic the Hedgehog series and in video games in general. The level and its music have also received positive opinions from critics. It has appeared in other games, such as Sonic Adventure 2, Sonic Generations, Sonic Mania, and Sonic Forces. Critics have noted a Green Hill-like aesthetic in levels of other games.