Chemical Plant Zone

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Sonic Retro emblem.svg Sonic the Hedgehog 2 (16-bit)
Chemical Plant Zone
Chemical Plant Zone
Second Zone, Sonic the Hedgehog 2 (16-bit)
Number of Acts: 2
Location: West Side Island
Level theme: industrial
Boss: Water Eggman
Maximum rings, Act 1: 195 + 130
Maximum rings, Act 2: 157 + 140
Underwater areas: Act 2
Non-English names:
Emerald Hill Zone | Aquatic Ruin Zone
For the Sonic Generations version of this stage, see Chemical Plant (Sonic Generations). For the Sonic Mania version, see Chemical Plant Zone (Sonic Mania). For the Sonic Forces version, see Chemical Plant (Sonic Forces).

Chemical Plant Zone is the second Zone of Sonic the Hedgehog 2. Like what Green Hill Zone is to the first game, Chemical Plant would become known as the signature level of Sonic 2 and see reappearances in games like Sonic Generations, Sonic Mania, Sonic Forces and Sonic Frontiers. The zone's graphics were created by Yasushi Yamaguchi.[6]


Set in Dr. Eggman's chemical plant, this zone is a token industrial cityscape with a network of pipes that pump blue chemicals that serve as the zone's many twisting pathways, and numerous loops for extra speed, along with the first-ever appearance of the infamous Speed Boosters, which would see much more frequent use in modern titles. The zone also features high-speed transport tubes that will take the player from one part of the zone to another location, harmful blue chemical globs that jump up and down between two points, and floating platforms to ride on. According to Yamaguchi, he originally wanted the zone's background to resemble a factory, but went with a cityscape instead to suit the Sonic series' art direction better.[6]

The second act's bottom sections are filled with a purple liquid known as Mega Mack. While it doesn't pose a great threat at first, the water level will rise when the player reaches a shaft full of moving yellow blocks. The player must quickly climb up to avoid drowning. It is possible to avoid this section entirely by taking the right path through the act. The boss at the end is Water Eggman.

In the original Mega Drive release of Sonic 2, the zone had numerous segments with glitched collision. According to Yamaguchi, this was due to the zone's high-speed nature, as Sonic can surpass the terrain's collision detection at high enough speeds.[6] Many rereleases of the game have since fixed these issues.

The zone shares tiles with Death Egg Zone, as time constraints prevented the developers from creating unique Death Egg graphics.[6]


Dr. Eggman’s chemical factory.
Run around inside the pipes that are stretched around all over the place!
Aim for the goal by dodging turntables and blowing chemicals.

Sonic the Hedgehog 2 JP manualMedia:Sonic2 MD JP manual.pdf[1] (translation by Vertekins)[7]

Flash through a high-tech maze built with pipes and ducts. Robotnik's flooded the factory with a pool of toxic liquid called "Mega Mack" that poisons Sonic in a few moments!

Sonic the Hedgehog 2 US manualMedia:Sonic2 MD US manual.pdf[8]

At first this stage was set to appear about after Zone 10. Although there would be fewer Acts this time, we thought having about 18 zones would be good, but having each zone stand out and fit in the story in a way that was easy to follow, in the end it dropped down to 11 zones, and Chemical Plant was placed as the second stage. In the end, it was a success (laughs).

Yuji NakaSonic Jam Official Guide[9]


Grabber sprite.png
Grabber — Spider Badnik, hangs from the ceiling and grabs Sonic. Then unless the player mashes Left and Right, or Tails can destroy the Grabber, it explodes and hurts/kills Sonic.
Spiny sprite.png
Spiny — Anemone Badnik, moves very slowly and spits out projectiles.

Technical information

Offset Description
0D CPZ Level Value
$2E02 CPZ Palette
$2E62 CPZ Underwater Palette
$D27C CPZ layer deformation info
$401B2 CPZ animated pattern load cue (0)
$40762 CPZ misc sprite mappings
$42376 CPZ object debug list
$453C0 CPZ and DEZ primary 16x16 collision index
$454E0 CPZ and DEZ secondary 16x16 collision index
$48774 CPZ act 1 level layout
$48A84 CPZ act 2 level layout
$4FAFE Animated background section in CPZ and DEZ
$B5234 CPZ/DEZ 16x16 block mappings
$B6174 CPZ/DEZ main level patterns
$B90F4 CPZ/DEZ 128x128 block mappings
$E5E2C CPZ act 1 ring locations
$E5F9E CPZ act 2 ring locations


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