Drainage System

Drainage System is a water-filled region of pipes and tunnels which features a large amount of water hazards and very few dry rooms. It is accessible early on from the Outskirts, but is significantly more difficult than the other route out of the region. Several points in the region feature long falls with no way of climbing back up, and may eventually force the player to take the bottom, flooded path towards the Garbage Wastes. Some rooms are almost completely flooded with only small pockets of air, and require extended dives to traverse.

Creatures
The following creatures will appear in Drainage System on easy and medium difficulties: The following creatures will appear in Drainage System on hard difficulty:
 * Bats
 * Hazers
 * Leeches
 * Lizards
 * Green
 * Magenta
 * Salamanders
 * Monster Kelp
 * Scavengers
 * Snails
 * Centipedes (Overgrown to Infant)
 * Dropwigs

Arena and Sandbox unlocks
The unlockable creatures, items and maps for in this area are:

List of gates to other regions

 * Gate to Outskirts (Requires 2 Karma)
 * Gate to Subterranean: Filtration System (Requires 4 Karma)
 * Gate to Garbage Wastes (Requires 1 Karma)

Tips

 * Reaching the Outskirts gate from the Filtration System gate is possible by using multiple spears to help traverse. In the vertical room where the only way forward is through a pipe in the ceiling, find and stick several spears into the opposite right wall while sliding down the left wall. Space these spears evenly from the top of the wall until slugcat can jump off the left wall to grab onto the lowest spear and climb up into the pipe.
 * Salamanders are formidable threats in the water, but are much less of a threat on land.
 * The leeches found in the region can be temporarily stunned using snails, however the same snails will also stun slugcat if they are too close.
 * In the lower, flooded region, slugcat will have just barely enough air to swim from one pocket of air to the next. If you bump into a wall and get slowed down, consider doubling back to the previous air pocket and trying again. Take advantage of the portable oxygen in bubble weed where available.