Games like Vampire Mansion
Games like Vampire Mansion include MiSide, ParanormalHK, Five Nights at Freddy's: Security Breach, IN HEAT: Lustful Nights, and Orc Massage. We matched them by the tags players give Vampire Mansion on Steam (Sexual Content, Nudity, 3D, Vampires, and Stealth): closest matches first, and among equally close ones the better-known games.

MiSide
Shared: Sexual Content · 3D · First-Person

ParanormalHK
Shared: Sexual Content · Nudity · Horror

Five Nights at Freddy's: Security Breach
Shared: Singleplayer · Stealth · First-Person

IN HEAT: Lustful Nights
Shared: Sexual Content · Nudity · Hentai

Orc Massage
Shared: Sexual Content · Nudity · 3D

Dark Siren
Shared: Sexual Content · Nudity · 3D

Mirror
Shared: Sexual Content · Nudity · Hentai

Resident Evil Village
Shared: Sexual Content · First-Person · Action

FreshWomen - Season 1
Shared: Sexual Content · Nudity · 3D

NEKOPARA Vol. 0
Shared: Nudity · Sexual Content · Hentai

Sex with the Devil
Shared: Sexual Content · Nudity · 3D

White Day: A Labyrinth Named School
Shared: Sexual Content · Nudity · Horror

NEKOPARA Vol. 4
Shared: Sexual Content · Nudity · Hentai

Summer Memories
Shared: Sexual Content · Nudity · Hentai

Clive Barker's Hellraiser: Revival
Shared: Sexual Content · Nudity · Action

Outlast 2
Shared: First-Person · Horror · Singleplayer

Romantic Escapades
Shared: Sexual Content · Nudity · 3D

The Wife Next Door
Shared: Sexual Content · Nudity · 3D

KunKunNight
Shared: Sexual Content · Nudity · Hentai

Lust from Beyond
Shared: Sexual Content · Nudity · Horror

Outlast
Shared: First-Person · Horror · Singleplayer

HuniePop
Shared: Sexual Content · Nudity · Hentai

NEKOPARA Vol. 1
Shared: Nudity · Sexual Content · Hentai

Seed of the Dead
Shared: Sexual Content · 3D · Nudity

