C13.1
Level C13.1 is a secret level that can be accessed through the left exit of C13. This level contains the water pump.
Description
The level contains a very simple node puzzle, allowing you to activate one of two doors. Activating the left door will break the water pump, flooding all the waterless levels and draining the underwater levels. Activating the right door will fix the water pump, restoring the levels to normal.
While the pump is broken, most levels have different layouts to their regular counterparts. This mostly consists of adding water currents and sometimes water enemies to waterless levels, and small layout changes to underwater levels to either make them possible or more challenging with no water.
While the water pump is broken, the player earns "water drops" instead of difficulty points. These function identically to difficulty points, and are required for 100% completion.