The Sewage Treatment Facility is the second level in Raider Zero. This level is much larger than Cargo Bay I, the previous level, and is partially submerged in water. In addition, numerous rooms in the lower part of the level are pitch dark, making it difficult to see without the NightVisionGoggles.
Upon entering this level from Cargo Bay I, Arkus Zei will encounter Gruen in this small room, who taunts him again before leaving. A Checkpoint will be directly in front of Arkus, and a chest will be on a platform above. Arkus can exit through the upper or lower path, but both lead to the same room.
Upon entering this room, Arkus will be attacked by a flying Sewer Speqtrid. If Arkus chose the upper path, he will be directly in the line of fire of a Miniturret (not on Easy difficulty), though he can use his shield to block the attacks. He must then jump across a series of platforms and confront another Sewer Speqtrid. An exit is on the upper right side of the room, and leads to 2i, a shortcut onward. If Arkus chose the lower path, he must use a moving platform to safely pass a bed of spikes and then jump across two platforms containing two Green Blobs. After doing so, he can proceed to the next room by falling down a pit.
Upon entering this room, Arkus will encounter a Volcano Plant on his left. He can then climb up a ladder to reach a platform containing a Save Point. If Arkus proceeds right, he will encounter a Green Blob in a pit and find a chest. Arkus can then return to the Save Point and proceed left up a series of floating platforms to reach the exit. Another Green Blob will be on the bottom left side of this room.
Upon entering this room, Arkus will be attacked by a Sewer Speqtrid (though it will not appear on Easy difficulty). Arkus must climb down a ladder while being shot at by a Miniturret on the left. A Volcano Plant awaits directly at the bottom of the ladder if on Medium difficulty or higher. Arkus must then jump down some platforms to reach the section of this room directly above the water level. A RoofCannon will be patrolling the ceiling, and a Green Blob will be on the ground. Arkus can climb up a ladder to reach a platform with another Green Blob on it. Next, he can jump up some platforms to reach a chest with a Homing RoofCannon patrolling the ceiling above it. After returning to the main path, Arkus must jump down a pipe into the sewage to access the lower exit into the next room.
From the previous room, Arkus will emerge from the top left exit of this long, submerged room. He will encounter two Arrowheads, one patrolling the middle, and the other patrolling the bottom of this part of the room. The lower left exit leads to 2g. If Arkus swims right, he will encounter a Volcano Plant. Here, Arkus can swim down into a small area guarded by an Arrowhead and containing 2 chests. Directly above is an exit leading to 2f. If Arkus continues right, he will pass a Sewer Speqtrid and can descend into a pipe, guarded by an Arrowhead. It leads to the lower right exit of this room, which leads to 2m, the return passage from after the boss. If Arkus bypasses the pipe, he must swim through some narrow passages covered with spikes and will later encounter a Volcano Plant and an Arrowhead at the end of the passage. The exit from here continues around the loop to 2j.
The upper central exit from the previous room leads to this small room. A Homing RoofCannon will be patrolling the ceiling. Arkus can jump out of the water onto dry land. A Checkpoint will be on his left. He can also jump across a bed of spikes to a chest on a ledge.
Upon entering this room from 'In the Bile', Arkus will confront a Volcano Plant (excepty on Easy). He must then swim up to a passage with a patrolling Arrowhead. Arkus can then swim through the pipes on the left which are laden with spikes, encountering a Sewer Speqtrid if on Hard difficulty. After emerging from the pipes, he will encounter another Arrowhead. He can then swim through a narrow series of passages to the exit on the top left side.
In this small room, Arkus can jump out of the sewage and onto a platform with a patrolling Nnenbot. There will also be a door requiring a Red Keycard to open, but since it doesn't exist, the door can never be opened. Arkus can jump back into the water on the right and find a chest.
Arkus will emerge from the upper left side of this room if he entered from the 'Stretch of Foulpins'. This room will be dark, making it hard to see. Arkus can climb down a ladder in the path and confront a Green Blob before reaching a chest. If Arkus returns to the main path and continues right and jumps down to a ledge, he will encounter two more Green Blobs. Another ladder will lead down into a small area with a Nnenbot and a chest. After returning to the main path, if Arkus attempts to access the top right passage with the Green Blob by climbing the ladder, he will only fall down into the bed of spikes below. He must instead jump directly from one platform to the other, ignoring the ladder. At the far right, a ladder leads down to 'Pollution', but a secret passage is hidden to the right of this, in the middle of the pipe downward.
This room can be entered from the upper right exit in 'In The Bile'. If on Hard difficulty, Arkus will be immediately confronted by a Sewer Speqtrid. Arkus must then swim to the top part of the room through a passage and avoid some spikes. The top corridor has a patrolling Arrowhead and a Volcano Plant on a platform. Next, Arkus must swim right, and then through a series of narrow passages containing spikes and two Arrowheads. At the end, Arkus will enter a large room and encounter Sewer Speqtrids (1 on Easy, 2 on Medium, 3 on Hard). The exit is on the top.
After entering this room, Arkus can jump onto one of two platforms on dry land. A Green Blob is patrolling the left platform, and a RoofCannon is above the right one. From the left, Arkus can take a ladder that reaches a platform with a Checkpoint. He can also use an exit on the right, leading to the descent into the lower part of the map. However, at this position in the room, Arkus will be in the sight of a Sewer Speqtrid (if not on Easy difficulty). Arkus can also take a moving platform on the left to reach the top platform, which is in the range of a Lightning RoofCannon. From there, Arkus can climb up a ladder to 'The Pipes' for an easy shortcut to the start of the level.
Upon entering this room, Arkus will encounter a Photon RoofCannon patrolling the ceiling (if not on Easy difficulty), a Hyperbeamer right in front of him, and an Acidragon on the upper platform which can be reached by using the barrels. From the upper platform, Arkus can reach a chest on the left. Arkus must proceed to the right and jump down to a platform. There is a door here that leads to the Inner Quarters guarded by another Hyperbeamer. A Green Keycard is needed to open this door, which will serve as a shortcut later in the game. To reach the next room, Arkus must then climb down a ladder, which is in the line of fire of a Miniturret. This exit leads to 2o.
This room can be reached from above, via 2e, or below, via 2n. If entering from below, Arkus must swim through a narrow passage with spikes and a rotorsaw, while being rained on by a Volcano Plant (except on Easy). He can then head down to a treasure chest guarded by an Arrowhead, or up, through a narrow passage with spikes and another Arrowhead to a large area with a Sewer Speqtrid. The exit is then just past the previously-mentioned Volcano Plant.
If entering from 2Ag, Arkus will confront a Sewer Speqtrid immediately after arriving. He can swim up to the upper left passage and open a chest. Next, he must navigate a narrow passage and avoid Rotorsaws. A Volcano Plant in a larger room also awaits Arkus. He must later navigate through a winding passage, avoiding more Rotorsaws and two patrolling Arrowheads. At the right side of the room, Arkus will confront another Sewer Speqtrid before reaching the exit leading to the start of the level.
A bed of spikes will be directly left of the ladder that Arkus could have used to get to this room from the previous. Arkus must drop down some platforms on the right side and will encounter a patrolling Homing RoofCannon to his left. A Green Blob will also be on the large platform to Arkus's left. He must then drop down some platforms on his left side and onto another platform containing yet another Green Blob. A Nnenbot will be on a platform in the right. In the centre, a lower platform will contain an Acidragon. Another Acidragon will be on a lower, solid platform. Next, Arkus must take a series moving platforms to continue downwards and avoid spikes. However, while doing so, he will be in the line of fire of a RoofCannon. On the bottom of the room, a Volcano Plant awaits Arkus (if not on Easy difficulty). The exit is on the left.
After entering this small room, Arkus must climb up a ladder to reach a platform containing an Acidragon. Then, he must drop down a series of platforms on his left and be careful of two Green Blobs. The hole in the lower left leads to the next room.
An Acidragon will be patrolling the solid platform at the top of this room. Arkus has the opportunity to use a Save Point before proceeding to the sub-boss.
Arkus will confront the Necroparasite in this room, which will attack by possessing the corpses of dead Nnengrals. After defeating the parasite, Arkus can enter the door on the right.
Arkus must jump up to a platform containing an Acidragon. A Blue RoofCannon will be patrolling the ceiling. Next, Arkus must climb down some ladders and avoid two Rotorsaws rotating in opposite directions. He will land on a platform with another Acidragon. Arkus must then drop down to another platform while avoiding a Rotorsaw. The lowest platform of this room contains a Green Blob, and the exit is on the lower left. Note that the two Rotorsaws moving anticlockwise will not appear on Easy difficulty.
Arkus should move right when dropping to reach a chest. Dropping down from here leads to the ground and some easily avoidable spikes. Coinciding with the room's title, Arkus will not be able to return up once he enters this room from the hole. A Lightning RoofCannon will be patrolling the area directly underneath the platform with the chest. Arkus can head right to enter another room (2t). There is an inaccessible door in the upper right.
To proceed with the level, Arkus must head left. He will encounter a Green Blob on the ground and a Nnengral Zombie on a platform, a tough enemy which will come back to life shortly after being defeated. If Arkus kills this particular one, it will drop a pair of NightVisionGoggles, allowing him to see better in dark rooms. Arkus must climb up a ladder and enter a pipe to reach the next room (2u).
In this room, Arkus will encounter a Nnengral Zombie on a platfrom. The door in this room will lead to 'The Crusher' (2Bb), but requires a Green Keycard.
In this dark room which can be accessed from 'No Turning Back', Arkus will encounter an Acidragon Zombie, a stronger version of the Acidragon. He can drop down a platform to continue with the level, but he should go left first to enter another room. If Arkus drops down the platform, he will be drop into the water and be attacked by a Sewer Speqtrid if on Medium difficulty or higher. There is a chest on a platform just above the water. Arkus must swim around a Rotorblade and into a pipe leading to the next room (2x).
Arkus will enter this dark room by going left in the previous area. He can drop down a platform or take the ladder to reach the ground, which contains a Nnengral Zombie. After killing or avoiding it, he can go left and jump up to a ledge with a chest, which is guarded by a Homing RoofCannon (except on Easy). Arkus can then enter a pipe to reach the exit on the lower left.
If Arkus enters from the previous one, he cannot enter the door because it requires a Blue Keycard. He must return to 2u and continue around the loop clockwise.
After entering this room, Arkus must swim to the upper passage past two Rotorsaws (1 on Easy). The passage contains a patrolling Arrowhead, and a bed of spikes is directly above the pipes leading to the entrance. After doing so, he must avoid two more Rotorsaws (1 on Easy) and reach a larger area containing a Volcano Plant and a Sewer Speqtrid (both not on Easy). Finally, Arkus must avoid another Rotorsaw and swim down a pipe to the exit on the lower left.
In this room, Arkus must first swim around a Rotorsaw. On Hard difficulty, there will be a Volcano Plant here, and a Sewer Speqtrid will attack him from below. Hey must then continue between a corridor laden with spikes, and down an another corridor with two more Rotorsaws. Spikes will also line the ceiling. A pipe in the bottom of the room leads on with the level.
Arkus can go right or left when he enters this room. If he goes right, he must only avoid one Rotorsaw before reaching the exit to the room on the right. If he goes left, he must avoid more Rotorsaws and spikes (there's a lot less spikes on Easy) before reaching the left exit. While crossing this room, he can access two side passages with chests.
In this room, Arkus must navigate through some small passages, avoiding spikes (there's less spikes on Easy) and the 3 Arrowheads patrolling them. If not on Easy difficulty, he will also be attacked by a Sewer Speqtrid as he nears the right side of this room. The exit is on the top right.
Though this room is still dark, Arkus can jump up to dry land upon entering. A chest on the upper platform will be guarded by a Rotorsaw and an Acidragon Zombie.
After entering, Arkus will be attacked by a Sewer Speqtrid. He can open a chest on a ledge in the water. After that, he can jump onto dry land and use a Save Point, though being careful not to be hit by a Homing RoofCannon. The door on the upper platform leads to the level boss.
Arkus will be attacked by the massive Toxikraken after jumping down to the centre platform of this room. The exit is the door to the left, but Arkus can also enter a secret room if he swims through a passage in the lower left side of the room that opens on returning to the area after killing the Toxikraken.
Arkus will encounter Gruen again in this room, who taunts him about his parents. After leaving, Arkus must drop down some platforms, climb up another set, and up a ladder to reach the next room. If he reenters the room, he will encounter an Acidragon Zombie on a platform and a Green Blob on the ground.
Arkus will encounter an Acidragon Zombie after reaching the lower platform of this room from the ladder. Next, he must climb up another ladder and take some moving platforms to reach the upper part of the room, all while avoiding spikes. A Miniturret will be shooting at him while in the lower part of the room. Further up, if not on Easy difficulty, another one will also be present further up. Arkus can take a moving platform on the left side of the room back down to reach a chest. At the top of the room, if on Hard difficulty, there will be a Photon RoofCannon. Arkus must go through the exit on the left, as the door requires a Blue Keycard to open.
Arkus can jump up to dry land after entering this room. The door on the left, requiring the Blue Keycard, leads back to 'Nothing to see here' (2w), and blocks Arkus if he descended the Ascent passage. He can climb up the ladder to reach the upper platform, containing an Acidragon Zombie and a chest. If Arkus jumps up in the upper right side of the screen, he can grab hold of a hidden ladder, leading to a secret room (Be).
If not on Easy difficulty, Arkus will be immediately attacked by a Sewer Speqtrid. He then has the opportunity to use a Checkpoint. Arkus must drop down into the water, where another Speqtrid will be waiting for him, though only on Hard difficulty. He must go through a pipe on the lower right side to continue. This room and the remaining section of the Lower Loop can be reached before defeating the bosses by descending the Ascent passage.
A Sewer Speqtrid (if not on Easy difficulty) will attack Arkus after entering this room. Arkus must navigate past a rotorsaw (2 on Hard) to the upper passage, avoid an Arrowhead, and swim between spikes and another rotorsaw (if not on Easy). If on Hard difficulty, two Volcano Plants will be shooting at him while he does this. After that, Arkus can enter a small passage in the upper part of the screen and open a chest. However, he will be attacked by another Speqtrid before doing so, if not on Easy difficulty. Arkus must then navigate through the lower corridor, avoiding another Arrowhead, before reaching the exit on the top right. This room is also filled with Rotorsaws. One less will appear if Arkus is on Easy difficulty, and one more will appear on Hard. On Hard difficulty only, two Volcano Plants will also be in the room.
Don't you just love these revolving blades of doom?
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Arkus must avoid a Rotorsaw immediately after entering this room. He can swim between two beds of spikes to reach an exit (leading to a relic), or continue upwards to return to the start of the level. If he continues upwards, he must navigate through a horizontal passage filled with spikes. He can swim up the left vertical passage to reach a chest, but he must also avoid a Sewer Speqtrid, if not on Easy difficulty. To continue on with the level, he must swim up the right vertical passage and avoid numerous Rotorsaws and an Arrowhead before reaching the exit on the top left. This passage will return Arkus to 'Knifed in the Night' (2n). Descending this passage is possible, but costs a lot of health.
This aptly-named dark room can be reached through the secret passage in 'The Pipes'. Arkus must wade through sewage to reach the door to the relic room on the right.
This room has a Doom Roof, so you need to move quickly. Immediately after entering, head right past the Acidragon and drop down the pit, sticking left to avoid the spikes at the bottom. Climb up the ladder, head left, past a second Acidragon if on Hard and drop down the small platforms with Green Blobs. You will likely get poisoned here. Head right past the Nnengral Zombie and the Rotorsaw (Hard only) drop down; there's a Volcano Plant just here (except on Easy). The following passageway drops into the water, climbs out and plunges back in, passing three Rotorsaws (two on Easy, five on Hard) on the way, before reaching the exit.
An extremely narrow passage with two Rotorsaws (three on Hard) leads to a platform with an Acidragon. From here, climb past two more Rotorsaws to the platform with the exit, guarded by a Green Blob.
The Relic Chest lies just below the entrance, guarded by an Infected Nnengral, a strong Nnengral variant that isn't encountered in regular gameplay until the Domed Forest.
This room can be entered via the secret passage in the lower left in 'Den of the Kraken'. Arkus can jump onto dry land and confront an Acidragon Zombie. The door leads to the relic room.
This room contains both a Relic chest on the same platform as Arkus and a regular chest on a platform below. A Doom Roof forces Arkus to move quickly and to reenter the room to obtain the second chest.
This room can be accessed using the hidden ladder in 'Reeking Tunnel'. Arkus will confront a Nnengral Zombie after entering. He must then jump over two spike pits while avoiding the attacks of two Volcano Plants, both located in the spikes. Grenades can be useful here, to kill the Volcano Plants. Next, he must use a moving platform to reach the the door leading to the relic room on an upper ledge.
Arkus will emerge on a small platform over spikes after entering. A Lightning RoofCannon will be patrolling the ceiling. He can jump down onto the lower platform with the relic chest.
The sub-boss of the Sewage Treatment Facility is the Necroparasite and is fought in the 'Bubonic Plague'. The main boss of the level is the Toxikraken and is fought in the Den of the Kraken. More information about both bosses can be found in their individual pages.
