The Erosion Counter, referred to internally as 侵食度, is a mechanic in .flow that affects several aspects of the game. The counter will generally increase after witnessing disturbing events and will also increase a small amount if caught by chasers or otherwise harmed. The higher the count is, the more "eroded" Sabitsuki will become, causing certain things in her dream world to distort. It is possible to lower the Erosion Counter via a few means, mostly involving the Sugar Hole.
Little Sabitsuki in the Parade Ward is also affected by the Erosion Counter, her condition worsening the higher the Counter. If the Erosion Counter is 100 or greater, the Rust Menu Theme can be obtained from her.
There are a couple ways to observe how high the Erosion Counter is in-game. The most immediately noticeable is in Sabitsuki's Room. As the counter increases, bloodstains will become present in the room, as well as other changes.
| Erosion Counter | Changes |
|---|---|
| 0 | None. Little Sabitsuki will be in perfect condition. |
| 50 | Blood present by the bed. Little Sabitsuki will be coated in blood, seemingly ill. |
| 100 | Larger bloodstain appears by the bed. Little Sabitsuki will slouch, blood seeping into her bedsheets, seemingly terminally ill. Interacting with her at this point will grant the Rust Menu Theme. |
| 150 | Another bloodstain appears on the wall beside the television. |
| 180 | Sabitsuki's computer is outfitted with unknown equipment with red wiring. |
| 200 | Several smaller bloodstains are present on the north walls. |
| ≥250 | The Erosion Event will trigger every time Sabitsuki or Rust wakes up until the Erosion Counter is reduced below 250. |
Raising Erosion
The following actions will raise the Erosion Counter:
- Witnessing the Blood, Pus, and Rust & Childbirth events (+50 points for first time; +10 points for every subsequent visit)
- Attacking the Kaibutsu at the Sugar Hole (+15)
- Getting caught by a Kaibutsu in the Orange Maze, Cleaner World, Womb Maze (in the Corrupted Purity area), or the Blood Maze (if attacked) (+10)
- Getting caught by a Kaibutsu in Cloud World, or attacked by a Fetus (except in the Corrupted School event when playing as Rust) (+3)
- Being touched by a Fetus increases the counter by 3 points. However, the four Fetuses that chase Rust when she is about to enter the Corrupted School do not raise the counter.
Lowering Erosion
The following actions will lower the Erosion Counter:
- Buying food or drink at the Sugar Hole. More expensive meals will deduct more points from the Erosion Counter.
- Spending 100 Yen (-5 points)
- Spending 200 Yen (-10 points)
- Spending 300 Yen (-20 points)
- Interacting with Oreko with the Diving Helmet effect equipped (-10)
Note that, while playing as Rust, the Sugar Hole is completely empty and Oreko no longer appears, leaving her with no methods of lowering the Erosion Counter.
Lowering the Erosion Counter will remove the blood in Sabitsuki's Room and will slowly heal Little Sabitsuki. However, the bloodstain on the keyboard, if triggered, can never be removed and will remain for the rest of the game.
Trivia
- Contrary to popular belief, the Erosion Counter by itself does not cause blood to appear on the keyboard. This is actually caused by the Blood, Pus, and Rust event. This rumor likely arose from the event's massive Erosion increase, enough to always create new bloodstains in Sabitsuki's Room.
- This is internally handled by Switch 225, named 吐血, which roughly translates to "vomiting blood".
- The minimum amount of Erosion required to beat the game is 42, assuming all sources of Erosion are completely avoided except for the 14 unavoidable Fetuses in the Rust Corridor, which raise it by +3 each. In practice, this is very unlikely to occur: It is extremely difficult to avoid the Fetuses on the way to the Empty Boxes, thanks to their bursts of speed and Rust's lack of Effects to dodge them with.
Gallery
Sabitsuki's room at 0 Erosion points.
50 Erosion points.
100 Erosion points.
150 Erosion.
180 Erosion.
200 Erosion.
