Games like The Innsmouth Case
Games like The Innsmouth Case include Dagon: by H. P. Lovecraft, The Test, The Wolf Among Us, Firewatch, and The Casting of Frank Stone™. We matched them by the tags players give The Innsmouth Case on Steam (Lovecraftian, Choose Your Own Adventure, Multiple Endings, Visual Novel, and Story Rich): closest matches first, and among equally close ones the better-known games.

Dagon: by H. P. Lovecraft
Shared: Lovecraftian · Visual Novel · Atmospheric

The Test
Shared: Choose Your Own Adventure · Multiple Endings · Story Rich

The Wolf Among Us
Shared: Multiple Endings · Story Rich · Choose Your Own Adventure

Firewatch
Shared: Story Rich · Atmospheric · Mystery

The Casting of Frank Stone™
Shared: Multiple Endings · Story Rich · Horror

Raging Loop
Shared: Visual Novel · Mystery · Story Rich

The Test: Hypothesis Rising
Shared: Multiple Endings · Choose Your Own Adventure · Visual Novel

The Witcher 3: Wild Hunt — Remastered
Shared: Story Rich · Atmospheric · Fantasy

What Remains of Edith Finch
Shared: Story Rich · Atmospheric · Mystery

Suzerain
Shared: Choose Your Own Adventure · Visual Novel · Story Rich

Roadwarden
Shared: Choose Your Own Adventure · Text-Based · Story Rich

Homicipher
Shared: Visual Novel · Multiple Endings · Horror

The Room Three
Shared: Mystery · Lovecraftian · Atmospheric

No, I'm not a Human
Shared: Horror · Story Rich · Multiple Endings

INSIDE
Shared: Atmospheric · Story Rich · Horror

STEINS;GATE
Shared: Visual Novel · Story Rich · Multiple Endings

Tiny Bunny
Shared: Visual Novel · Story Rich · Atmospheric

Scarlet Hollow
Shared: Visual Novel · Story Rich · Multiple Endings

Oxenfree
Shared: Story Rich · Atmospheric · Mystery

Life is Strange: Before the Storm
Shared: Story Rich · Atmospheric · Choose Your Own Adventure

Danganronpa 2: Goodbye Despair
Shared: Visual Novel · Story Rich · Mystery

Zero Escape: The Nonary Games
Shared: Visual Novel · Story Rich · Multiple Endings

Outer Wilds
Shared: Story Rich · Mystery · Atmospheric

Slay the Princess — The Pristine Cut
Shared: Visual Novel · Choose Your Own Adventure · Story Rich