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Sonic the Hedgehog 2
Chemical Plant Zone

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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!

— Description, Sonic the Hedgehog 2 (16-bit) United States instruction manual[1]

Chemical Plant Zone (ケミカルプラント[2] Kemikaru Puranto?, lit. "Chemical Plant") is the second Zone of Sonic the Hedgehog 2, its various ports and remasters, and the lock-on game Knuckles the Echidna in Sonic the Hedgehog 2. it is Dr. Robotnik's chemical factory[2] on West Side Island. As with most other Zones in this game, Chemical Plant Zone consists of two standard Acts with a boss fight at the end of Act 2.


A heavily industrialized area that contains pools of Mega Mack, Chemical Plant Zone is full of light gray buildings with warning signs, some of which are covered by transparent tubes carrying blue Mega Mack. These tubes have yellow platforms on top of them that the playable characters can stand on. The plant is as well full of other tubes of different kinds.

In the background, some tall, red buildings can be spotted underneath a crimson sky. Also, at the bottom of the background, there is a gigantic and toxic, lime-white lake of chemicals.


During his hunt for the Chaos Emeralds, Dr. Robotnik would invade all of West Side Island, including Chemical Plant Zone, filling said Zone with Badniks.[3]

Chemical Plant Zone soon after became the second Zone that Sonic and Tails would travel through to put a stop to Robotnik's operations. On their journey through the Zone, they eventually locate the doctor in the Egg Poison, which they have a battle against. After his vehicle is defeated, Robotnik flees, while Sonic and Tails head to Aquatic Ruin Zone.


It has many difficult obstacles, often requiring fast reflexes, such as the player having to jump very quickly over the gap. There are still loops, and other places where the player can gain lots of speed. It is actually possible to outrun the screen sometimes.

High-speed warp tubes, miscellaneous terrain features that suck the player in and deposit them at the other side of the tunnel, wind across the level. These cause no damage nor have any effects other than transportation. Yellow-clad pipes filled with blue chemicals spiral through almost the whole map. They can have very steep drops and may climb after a drop. These can sometimes end badly, such as if one throws the player onto a cliff into the water. To avoid dangers from these, the player should stay alert while moving.

Blocky collections of yellow/purple squares move back and forth periodically. The player must jump onto them and then carefully jump onto either the other square next to it or solid ground. These require a knowledge of the game physics and quick reflexes. For players who do not have these, the moving squares can be the hardest part of the Zone.

The rising Mega Mack during Act 2 sees the water level rising and the only way to escape to land is by climbing up rotating blocks, as explained above. This is a very dangerous segment, as the player is not only at risk of drowning, but also at risk of being crushed by the rotating blocks. However, it is easily avoidable and completely skippable if the right path is taken.

There are also blue chemical jets known as blue blobs;[4] these require very quick reflexes, as they can harm Sonic. These shoot from one tube to another, or in a parabolic path.


Act 1

The Act starts with six Rings and four floating platforms. The road slants before bending downwards and splitting into two paths. The top path is marked with a Super Ring monitor. The roads cross each other several times. The lower road slides the player towards a three-four loop, with seven Rings. At the end of this road is a red Spring, splitting the path into two again.*

Jump over this Spring and they will find another Ring monitor and a Dash Panel. The panel allows them to zoom past another crossroads towards another slant where five airborne Rings can be collected. If the slant is taken with enough rightwards momentum the player can reach the next solid platform, which has an Invincible, Super Ring and One-Up monitor placed next to each other. The player will then encounter a Spiny in the tunnel, guarding the next obstacle: a tight group of rotating small blocks that act as solid platforms that can crush the player if they are not careful. Ascend right from there and they will find another Dash Panel which takes them through another series of crossroads, followed by four more loops and two regular loops with a Dash Panel in between.

The long road ends in a slant to the final section: a spiny attached to a wall is guarding three Rings and a high-speed warp tube, which the player can break the cover off to access. Both tunnels lead to the same terminal. The player can take the Spring attached to the cover to collect five more Rings. There is a Super Ring monitor parked next to the wall on the right. To the left is a short road towards another series of small blocks: Touching these will shift them down, accessing to the final section. The player will encounter two chemical chutes side by side. Clearing that will access the Goal Plate, completing the Act.

Taking the upper road at the start cross bends into a slant, followed by a short road into into a small wall, with a Grabber placed on the ceiling. Following that is another short wall, where two Spinys are placed atop it on the ground. The road bends down into a 3/4 loop which if taken with a spin, sends the player at high speed through a crossroads into a double quarter slant, awarding sixteen Rings. They will land on a yellow Sp0ring. Left of there is a narrow corridor with two chemical jets that shoot chemicals up and down at various intervals. Beyond that is a locked door and a tube spring.

*After the player spins into the spring, they will be sent back up the loop and to the next path marked with two quarter slants. There are two Spinys on the ground, followed by a high speed warp tube case and a Super Ring monitor. Holding the down button will take them through a long tube to the same spring mentioned above.**

Right of this spring is two more Spinys followed by a slant and two short walls. The road leads to a series of descending ramps taken by horizontal Springs placed into walls. A Dash Panel speeds them towards the slant and the final section.

**Holding left will take the player to the lower half of the Act. As soon as they are out there are two more Super Ring monitors and a group of Rings which can be collected by the Spring and Spin Dashing the double slant to the left, totaling thirty. To the right is a Shield monitor hidden behind the lattice parked by a short wall. Afterwards there is a series of obstacles: a Spiny and three sets of chemical chutes with gaps in between. A Grabber is occupying the first gap. Past there is a quarter slant, another Spiny and a Dash Panel which takes them across two loops and up a quarter slant. If they take off from this slant to the left with enough speed they will land on a corridor with three more monitors: two Super-Ring and one Shield, totaling thirty-five rings. The player can also take the leftwards Dash Panel which will lead them to another Super Ring monitor, a Star Post and a high-speed warp tube.

To the right of the Dash panel is a group of solid blocks and a moving floating platform that will help the player ascend the wall to the next section. The road bends down towards a flappable platform followed by a series of short walls. Dropping down and turning left will access a Star Post, a Super Ring and Shield monitor. To the right is some more chemical chutes. The route leads to the final section.

If the player makes the jump to the short walls they will encounter a Spiny and another warp tube. To the right of its exit is the last Star Post along with a series of floating platforms leading to a locked door. The route soon takes them to a chemical chute and the Goal Plate.

Act 2

The player starts at the top. A slant leads to a Spiny, then it is a long slide down a series of crossroads which if taken with enough speed, they can collect twelve rings and land on top of the wall with the Jump Panel to its right. Otherwise after crossing some steps they will need to ascend up a corridor of crush blocks. To the left the road ascends a bit towards another set of blocks, allowing the player to reach the Jump panels. However, if they touch these blocks and immediately turn back to the right they will access the section below, where an Invincible and a Super Ringmonitor can be obtained. To the right of the following slant are two Grabbers protecting a group of monitors (two Super Ring and one Shield). Ascending up the group of rotating platforms will take them along a corridor to the high-speed warp tube. The player can hold either left or down here.* Holding left will take them to the next section, where up to forty-four rings can be obtained. To the right of the exit are two Super Ring monitors. A left-facing Dash Panel will take the player up the wall and along the upside-down slant. Atop the wall is a Super Ring monitor and a gap with more solid blocks, though the player is more likely to touch the next Dash Panel and continue on. A Star Post can be found through this gap, followed by another one which can be found by jumping across the gap to the left. These two are treated as one checkpoint however. If the player falls through the gap they will respawn at an earlier point in the Act.

Past the second Dash Panel is another long slide to the left, which leads them across another Dash Panel, up a 3/4 loop and two quarter slants with a Super Ring monitor and a high-speed warp tube. Jumping in will lead to the third long slide, which is a long road that if taken with enough rightwards momentum, can reach the corridor at the top. Another set of rotating crush blocks need to be trespassed from above, followed by two short walls to a Dash Panel. If the player brakes after triggering this panel and jumps to the left they will find a hidden section, otherwise they will be encountering Mega Mack later in the Act. Short walls lead to a Super Ring monitor followed by a double quarter slant to the next Star Post. To the right of this post is another Dash Panel which zooms them to a double quarter slant with a gap across the middle. Through this gap is another Super Ring monitor and another Dash Panel which sends them through four loops. The long road soon bends down to a room with three monitors: two Super Ring and one Invincible. Along the long corridor is a drop, landing onto the platform that leads to the Act's boss.

*Pressing down will send the player to a different area. The rewards are not as generous as the left route, earning sixteen Rings. A slide takes them along two Dash Panels up two 3/4 loops, leading to a quarter pipe. A cluster of ten rings can be collected up there given enough momentum. The route leads to a narrow corridor leading to two floating platforms. There are two flappable platforms to the right of the second one that leads to a bottomless pit if fallen through. To the right is a Spiny attached to a wall and another high-speed warp tube, which takes them through some Mega Mack. Taking the spring up the wall on the left will ascend them to where a Super Ring monitor is located. The Dash Panel will take them through the rest of the level.

A Star Post is available at the start of the lower route, followed by a series of steps up to a narrow corridor, where a Super Ring monitor, a Grabber and a Locked Door are encountered. The road leads to back-to-back Springs followed by a descending platform, where they are standing atop a sea of Mega Mack. To the right are two horizontally moving small platforms that bounce off each other that will transport the player to the other side. If the player mis-lands they will fall into the Mega Mack. There are three platforms below with two gaps containing spike pits. The left platform has a Jump panel that helps them back to the top, while past the third platform is a group of downward steps leading to a One-Up monitor. Successfully passing the obstacle will lead to a Dash Panel, through the crossroads to arguably the most famous section.

The next section is a narrow vertical corridor with multiple groups of rotating crush blocks. As soon as the player arrives here, the doors close and the water rises. The exit at the top on the left has two downward steps followed by a long gap with two small platforms. The road bends into a narrow tunnel towards more flappable platforms sat next to a jumpable wall. Above are two circular-moving platforms that lead to another fast section. Triggering a Dash Panel will lead to a Star Post, two more loops, a gap with a Jump Panel, and a road that leads to the final section. Down two steps is another pit with a transportable platform with a red Spring on the left and a supporting platform for those who fall in on the right side. Through the long tunnel is the boss site.


Main article: Egg Poison

The Egg Poison, the boss of Chemical Plant Zone, from Sonic the Hedgehog 2.

The boss is Dr. Robotnik piloting a floating vehicle that can create sludge "bombs." He will hover over the pink water as his overhead canister fills, then and will drop them on the player once done. If that weren't hazardous enough, the battle is fought on a solid platform surrounded by considerably less solid edge segments. Many people have killed the boss only to die by falling off the bottom of the level on the dropping squares.


  • This Zone and Death Egg Zone both use the same tilesets.
  • The same rhythm of the background drums in Splash Hill Zone Act 1's music was reused from this Zone's.
  • During the credits of Wreck-It Ralph, Sonic can be seen running through Chemical Plant Zone.
  • Some Samsung phones feature a game called "Jump Boy", which features the music from Chemical Plant Zone.
  • This Zone marks the first-ever appearance of the Booster-based gimmicks, which would see much more frequent use in modern titles.
  • The game design document of Sonic the Hedgehog (Didj) mistakenly refers to Chemical Plant Zone as "Brickopolis Zone".[5]



Act 1


Act 2


Name Length Artist Music Track
"StH2 Chemical Plant Zone ~Mega Drive Version~" 2:10 Masato Nakamura



Sonic the Hedgehog 2 - Chemical Plant Zone Act 1 Walkthrough

See also


  1. Sonic the Hedgehog 2 (Sega Genesis) United States instruction booklet, pg. 12.
  2. 2.0 2.1 Sonic the Hedgehog 2 (Sega Mega Drive) Japanese instruction booklet, pg. 31.
  3. Sonic the Hedgehog 2 (Sega Mega Drive) Japanese instruction booklet, pgs. 4-5.
  4. Prima Publishing (1993). "Sonic The Hedgehog for Sega Genesis". Sonic the Hedgehog 1 & 2: Sega's Official Player's Guide. Prima Publishing. p. 83. ISBN 1-55958-335-5.
  5. Sonic the Hedgehog (Didj) game design document, pg. 8.

External links

  • Sonic 2 page at The GHZ has detailed information on all the Sonic 2 zones.

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