Once Sal reveals his true self, everything goes downhill from there. He manages to unleash the Sea of Death, turning everything blood red and creating a large source of uncomfortable imagery, to say nothing of the Red Ending.
The flashback with Sal chasing a young Wadanohara is awfully revolting, from the assault to possibly trying to rape her. It's a gameplay-based chase scene at that, and it's possible for him to catch her!
The entire last level of the game is a huge case of eyes in all the wrong places. The eyes in some corridors are also photorealistic, using Uncanny Valley as a means to unnerve the players.
When Princess Mikotsu appears, she locks Wadanohara in a Lotus-Eater Machine. Initially, things look more or less normal: it seems as if Wadanohara has woken up from a bad dream. But just below the surface, everything is dull and lifeless - all the colors are wrong, almost everyone says only "Hello", mirrors show Wadanohara is not truly happy, and nothing seems to actually exist beyond the town or within any house other than her own. After wandering around for a while, Wadanohara closes her eyes, and we see the true form of the illusion suddenly revealed: a town full of blood, littered with the mutilated corpses of Wadanohara's friends, and she doesn't notice! And then, to show her will being drained away, she opens her eyes again, and they've turned into a pair of giant pitch black voids, which gradually glow red, while she complains of feeling sleepy, with more and more disjointed speech.
Normal Ending 1 has Sal capturing Wadanohara and corrupting her to be on his side, with off-screen torture that has very unsettling rape subtext (and might possibly just be text). And this is all the while an injured Samekichi is helplessly watching.
