Oil Ocean Zone (Sonic Mania)

Oil Ocean Zone is the ninth Zone for Sonic Mania. This Zone is a re-imagination of the Oil Ocean Zone from Sonic the Hedgehog 2 for the Sega Mega Drive.

Overview
Like the original, the Oil Ocean Zone is an industrial area for extracting and processing oil. The entire region is a sea that has been blanketed by oil and is overcast by an orange sky with a lit horizon. Only some could and the obscured sun can be seen in it. The areas with solid footing consists exclusively of a network of metallic oil platforms and factories emblazoned with the Eggman Empire's decal, most of which are disposing oil into the sea. Along the roads are sections in purple and green with strange-looking ornaments.

As the player gets further into the Zone, the region becomes darker: the sky turns dark red, the oil pools become more frequent and the oil platforms' structures become more like buildings.

Story
After literally shooting themselves to the Oil Ocean Zone, Sonic, Tails and Knuckles find themselves once again in search of Dr. Eggman to stop him from abusing the Phantom Ruby. Making their way to the most polluted region of the Zone, the trio overcome another one of Eggman's attempts to crush them. Having not stopped Eggman yet though, the trio's continues their search, which takes them to a familiar location.

Gameplay
The oil pools in this Zone that the player can make contact with can be set ablaze by fire-based objects, like the Flame Shield or a Gohla's fireballs. This will create a field of fire that can damage the player should they touch it without protection, although it will eventually go out after a few seconds. Some edges also have yellow outcrops that crumble a second after the player touches them. There are also oil falls in the foreground that the player can climb by entering them and continuing to jump inside them.

Among the gimmicks in this Zone are elevators that can take the player up or down and oil slides that the player will ride automatically once they touch them. There are also green flame-propelled gas-burn platforms that get catapulted into the air in intervals, which the player can hitch a ride on. Some green pipes have as well as spikes that slide along them.

A recurring effect in the second Act of this Zone is that the screen will gradually turn more and more smoky as time passes, making it harder to see enemies or obstacles, and navigate the surroundings. Should the air become too smoggy, the player character will begin to lose Rings gradually (similar to a Super State), though this effect cannot kill the player character. To clear up the air, the player must grab and pull chain switches that hang from the ceiling. However, this effect is only temporary. The second Act also features springs that must be pushed back by the playable characters before they can launch them forward.

The second Act features submarines that act as mini-levels within the course of the stage. Entering one will require the player character to complete a brief platforming section within before exiting into a different part of the main Act.

Like in the original Oil Ocean Zone, this Zone features Cannons which throw the player back and forth around the Zone, and fans that can blow the playable characters away or take them through the air.

Act 1
Act 1 is almost identical to both acts of the original Oil Ocean Zone in Sonic the Hedgehog 2, albeit much longer. One big difference is the presence of the Fire Shield, which will force the local oil to combust. Beating the boss of this Act will set the entire Zone on fire, bringing the player to Act 2.

Act 2
Act 2 borrows features from Sandopolis Zone Act 2 in that the player must keep pulling pulleys under a time limit to prevent the Zone from filling up with deadly gas. This Act also features prominent use of submarines, which will take the player into the oil (and as a result pausing the gas effect). The players must navigate these small submarines in order to find the exit which will launch them to further parts of the Act.

Act 1
The Act 1 boss is a floating utility robot with a large wrench. Initially it will fly back and forth and toss the wrench at the protagonists before eventually going into the background and turning a release valve. When this happens, the green platforms below the character will become active and they must stand in the center platform or risk being shot up into the spikes that line the ceiling of the area. The boss can only be damaged when it is in the foreground.

Act 2
Dr. Eggman pilots a large submarine shaped like an Octus for this encounter. The machine's main method of attack is to submerge two of the three available platforms (forcing the character to jump to the third platform or descend into the oil), summon the bullet shooter tentacles from the Heat Arms miniboss from Lava Reef Zone, and employ the same tactics as the original Oil Ocean Zone boss (deploying a snake-like object with a pointed tip that flies at the protagonist and a laser cannon that fires three times, including scorching the ground if fired at platform height). Hit the Octus submarine eight times to end the battle (as with the Heat Arms fight, destroying the bullet shooter tentacles can be done but does not contribute to the victory condition of the battle).

Trivia

 * The fire animation that occurs after beating Act 1 is very similar to the one that occurs after Angel Island Zone Act 1 from Sonic the Hedgehog 3.
 * The Pull Switches used to relieve the smog in Act 2 is similar to a mechanic in Sandopolis Zone Act 2 in Sonic & Knuckles, in which the player must also use Pull Switches to turn on the lights in order to keep the ghostly Hyudoro at bay.
 * The submarines seen in Act 2 are based on the ships seen in Marina Madness in Knuckles' Chaotix.