Loot River

These are the illusionary walls in runs that cover secret passages, you need to hit them to uncover it.

The way to discover these is noticing the red 'X' in the water reflection of the wall you can see if there is no platform in the way. The actual wall itself looks no different. These may be tricky to see when running through an area, keep an eye out. The minimap may also sometimes give a hint that there's an area behind a wall nearby.

10 minute easy method on fresh save slot

1. Start a fresh save in slot 2, and uncover the secret passage in the tutorial in the upper left of where you spawn. Then continue the tutorial until the boss, die here or kill it either works.
   
2. When you respawn for the next run, simply speedrun Sunken Village to get to the First City area. The First City has another guaranteed illusionary wall next to Rupert. Just rush through this area not fighting again to find this quickly. If you've played the game, you'll know what to look out for to find him.
3. After getting this illusionary wall, continue to speed through First City fighting no enemies to quick and easily get to the Chapel of Revenants. In this area, the first open room with the dead body in, before reaching the Gwen fight room, there is a guaranteed illusionary wall in the upper right. (thanks to MUhanfeng for this one)

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