Chemical Plant Zone

From Sonic Retro

Sonic Retro emblem.svg Sonic the Hedgehog 2 (16-bit)
Chemical Plant Zone
Chemical Plant Zone
Second level, Sonic the Hedgehog 2
Number of Acts: 2
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).

The second zone in Sonic 2, Chemical Plant Zone is Dr. Robotnik's chemical plant, full of tubes and floating platforms. In the second act, he uses a poisonous new substance called "Mega Mack" to try to kill Sonic, though mechanically, it's just pink water. The zone shares palettes and tiles with Robotnik's Death Egg Zone.

This zone marks the first-ever appearance of the infamous Speed Boosters, which would see much more frequent use in modern titles.


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 2 US manualMedia:Sonic2 MD US SonicJam manual.pdf[4]

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


  • Grabber - Spider enemy, hangs from the ceiling and grabs Sonic. Then unless Tails can destroy the Grabber, it explodes and hurts/kills Sonic.
  • Lander - Anemone enemy, moves very slowly and spits out missiles.

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


Sonic the Hedgehog 2 (16-bit)
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