Sonic Boom: Rise of Lyric
Ocean Purification Plant (オーシャン・プラント Ōshan Puranto?, lit. "Ocean Plant") is the sixth area of Sonic Boom: Rise of Lyric. It is an undersea facility powered by the Tidal Crystal, which filters out all the muck and gunk dumped into the sea during Lyric and the Ancients' war in the past. It is also here that Q-N-C was built and programmed.
The Ocean Purification Plant is divided into two sections. The first is a metallic compound and storage facility located below the sea, amidst a coral reef. It is mainly made of dome-like industrial rooms with smaller tunnels connecting them, some of which are glass tubes leading through the sea. The Ancients' architecture is displayed in the markings adorning the surfaces. Along the walls are windows showcasing the sea. The rooms are lit up by green lights from all around.
The first section of the Ocean Purification Plant is filled with various tubes, vats and pipes that contain either water or a green liquid. These vessels align the walls and bottoms of the rooms. There are also large pools of toxic waste from the plant's cleaning procedures which contain a stinking mineral removal. Leading over these pools are scaffolds and platforms. The plant also has several control panels and is equipped with a security system.
The second section of this level takes place inside a rift in the sea created by the Tidal Crystal. Here, immense walls of suspended water appear on both sides. Undersea rock formations stick out from both below and through the water walls, showing an abundance of coral reefs, undersea flora and sea snails. Amongst them lies abandoned pirate-like ships from Lyric's armada. At the end of the rift lies a fortress from the Ancients with a tower that contain the Tidal Crystal and the Angler's dock.
A thousand years ago, the Ancients hid the Tidal Crystal in the Ocean Purification Plant so that Lyric could not find it. Following Lyric's uprising, this location became the first site of Lyric's attack, which ended in failure.
In the present day, Sonic was joined by Amy to the Ocean Purification Plant to find the Tidal Crystal, despite wishing to go alone, and was soon joined by Q-N-C. When they found what they thought to be the Tidal Crystal however, they were attacked by the Tunnel-Bot. Escaping the robot, Q-N-C revealed that the Crystal they found was fake and that real one was further inside.
The hedgehog duo continued to the center of the Ocean Purification Plant (where Amy had Sonic watch the scenario) where they found the real Tidal Crystal. Removing the Crystal made the Ocean Purification Plant crumble however, forcing Sonic and Amy to escape in the Angler.
In Ocean Purification Plant, the player passes through the processing plant, across the sea rift and into the sea fortress' tower. Like other levels in the game, Ocean Purification Plant features different puzzles the player has to clear to progress, which can be solved with the Enerbeam mechanic and Buttons. It also contains a few short speed level sections, where the player runs down a long path with speed-enhancing gimmicks while avoiding hazardous obstacles, and as well slower-paced areas for exploration and combat.
Since Sonic and Amy are playable characters for this level, Ocean Purification Plant contains all the gimmicks for their character actions, such as Spin Ramps, Spin Balls and Air Targets for Sonic and Balance Beams and Beam Swings for Amy. There are also large purple clamshells in the sea rift which work like Bounce Pads.
Environmental hazard in this level differs between sections. In the plant, there is waste leaking from nearby pipes, ground vents spewing toxic gasses, red-hot bars and even geysers of toxic which can intercept airborne players, all of which cause damage upon contact. Exclusively for Amy, her Balance Beams can crumble apart or have harmful containers roll on them. There are also Commando Husks which Parasite Snakes can possess, thus creating stronger and tougher enemies. In the sea rift, there are as well sea snails with spiky shells that cause damage when touched. These snails are found on any surface and can either move around in patterns or come together to form clusters of spikes
In Ocean Purification Plant, the player's objective is to obtain the Tidal Crystal. At the beginning, the player must move from the elevator leading into the level to the hall at the end of the path and collect the fake Tidal Crystal. The Tunnel-Bot will then appear and the player will enter a short speed level section. There, they will be chased by the Tunnel-Bot. The player must keep their distance from the Tunnel-Bot; touching it will cause instant defeat.
When entering the room after the speed level section, the player must press some Buttons below the front edge of the room to open an path straight up to the higher areas. From there, the player must defeat a few enemies and cross some pools of waste before arriving at an Enerbeam puzzle. There, the player has to fight off the Tunnel-Bot to access said puzzle. This puzzle will lower the toxic pool levels, allowing the player to proceed down there, where they have to pass through a door to another speed level section. There, the player will be chased by the Tunnel-Bot again while they have to dodge pipes.
After the end of the speed section, the player arrives at the sea rift. Here, the player must find and board two abandoned ships and fire their cannons at the fortress' walls to reveal some paths behind it. At the wall, the player must raise an anchor blocking the revealed path and then scale it. At the top, the player must defeat some enemies to open a puzzle that will take the player to the tower. Inside the tower, the player has to climb to the top where a puzzle must be solved to unlock the Tidal Crystal. Once the Crystal is obtained, the player enters Undersea Bolt.
The recurring boss of the Ocean Purification Plant is the Tunnel-Bot, the plant's Crystal guardian. It is encountered on three separate occasions during the level. For these boss battles, the player controls Sonic and Amy.
Overall, the Tunnel-Bot cannot defeated by the player in this level; rather, they only postpone this for the Undersea Bolt. In the first and third encounter, the player's only option is to escape it as touching the Tunnel-Bot causes instant defeat. In the second encounter, the player must keep throwing Destruction Troops at it with the Enerbeam until it retreats.
This level has the following total of collectable items:
- According to unused voice clips, the Ocean Purification Plant is filled with many fake Tidal Crystals to keep Lyric searching for the real Crystal. The minerals are used to create fake Tidal Crystals. They also say that the Ocean Purification Plant was the first site of Lyric's attack and the pirate ships found there are the remains of his forces.
- During Sonic Boom's development the stage was referred to as Ancient Template, rather than it's final name. It can be assumed that this was a placeholder name.