- For other similarly named levels, see Green Hill Zone (disambiguation).
Green Hill Zone is the first Zone of Sonic Blast. As with other Zones in this game, Green Hill consists of two standard Acts followed by a shorter third Act which contains the Zone's boss.
Like many other levels that share its name, Green Hill is a tropical Zone with trees, green grass, blooming flowers and waterfalls to mark the beginning of Sonic and Knuckles' adventure across South Island. The Badniks found in this Zone are similar to those of Emerald Hill Zone in Sonic the Hedgehog 2.
Act 1 is a very short, straightforward level with three loops and a small pool to jump across, while the second Act is longer, consisting of tubes that transport Sonic or Knuckles further down the level past a series of waterfalls. Both Acts have a hazard in the form of a spinning bridge with poles that will harm the player, similar to the spiked log bridges from Sonic the Hedgehog's iteration of Green Hill Zone.
||Sonic (or Knuckles) starts out the adventure in a tropical forest. Hills and valleys abound, and rickety wooden bridges cross treacherous rivers. Watch out for the piranhas and coconut-tossing monkeys!
— Sonic Blast US manual
||Ai-ai — Monkey-bot that drops coconuts on the player.
||??? — Buzzer-type Badnik that flies in the air and shoots.
||??? — Masher-type Badnik that jumps up and down to bite the player.