Games like Shiina Taki's Decameron
Games like Shiina Taki's Decameron include Mirror 2: Project X, Sweet Home, The NOexistenceN of you AND me, Volcano Princess, and The Hungry Lamb: Traveling in the Late Ming Dynasty. We matched them by the tags players give Shiina Taki's Decameron on Steam (Anime, Interactive Fiction, Multiple Endings, Free to Play, and Singleplayer): closest matches first, and among equally close ones the better-known games.

Mirror 2: Project X
Shared: Anime · Interactive Fiction · Multiple Endings

Sweet Home
Shared: Interactive Fiction · RPG · Visual Novel

The NOexistenceN of you AND me
Shared: Anime · Multiple Endings · Visual Novel

Volcano Princess
Shared: Multiple Endings · Anime · RPG

The Hungry Lamb: Traveling in the Late Ming Dynasty
Shared: Multiple Endings · Interactive Fiction · Visual Novel

Doki Doki Literature Club Plus!
Shared: Anime · Visual Novel · Multiple Endings

Far Away
Shared: Singleplayer · Visual Novel · Anime

NEEDY STREAMER OVERLOAD
Shared: Anime · Multiple Endings · Visual Novel

The Weeping Swan: Ten Days of the City's Fall
Shared: Interactive Fiction · Multiple Endings · Anime

Billionaire Lovers
Shared: Anime · RPG · Visual Novel

Otaku's Adventure
Shared: Multiple Endings · Anime · Visual Novel

Noctuary
Shared: Interactive Fiction · Anime · Multiple Endings

An alt girl for skoof
Shared: Anime · Visual Novel · Multiple Endings

Analogue: A Hate Story
Shared: Anime · Interactive Fiction · Visual Novel

Love Curse: Find Your Soulmate
Shared: Multiple Endings · Visual Novel · Singleplayer

Class of '09: The Re-Up
Shared: Anime · Visual Novel · Multiple Endings

Vampires' Melody
Shared: Interactive Fiction · Visual Novel · Anime

Lay a Beauty to Rest: The Darkness Peach Blossom Spring
Shared: Multiple Endings · Interactive Fiction · Visual Novel

Fox Hime
Shared: Anime · Visual Novel · Casual

My Vow to My Liege
Shared: Anime · RPG · Visual Novel

Long Live The Queen
Shared: Anime · Visual Novel · Indie

1 to 1 humanoid edible toys
Shared: Multiple Endings · Visual Novel · Interactive Fiction

Magical Princess
Shared: Multiple Endings · Anime · RPG

他人世界末 On-looker
Shared: Multiple Endings · Anime · Visual Novel