Games like Neptune Island
Games like Neptune Island include Poppy Playtime, Inside the Backrooms, The Exit 8, Buckshot Roulette, and Endacopia. We matched them by the tags players give Neptune Island on Steam (Puzzle, Horror, Retro, Exploration, and Dark): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · Puzzle · Dark

Inside the Backrooms
Shared: Horror · Puzzle · Exploration

The Exit 8
Shared: Puzzle · Exploration · Horror

Buckshot Roulette
Shared: Horror · Dark · First-Person

Endacopia
Shared: Horror · Puzzle · Exploration

SOMA
Shared: Horror · Dark · Psychological Horror

IMSCARED
Shared: Horror · Pixel Graphics · Puzzle

Garten of Banban
Shared: Horror · Puzzle · First-Person

Escape the Backrooms
Shared: Horror · Exploration · Psychological Horror

MOLE
Shared: Horror · Puzzle · Retro

Is this Game Trying to Kill Me?
Shared: Horror · Puzzle · Dark

Amnesia: The Dark Descent
Shared: Horror · Puzzle · Psychological Horror

Little Nightmares II
Shared: Horror · Puzzle · Dark

FAITH: The Unholy Trinity
Shared: Horror · Retro · Pixel Graphics

Bendy and the Ink Machine
Shared: Horror · Puzzle · First-Person

Sally Face - Episode One
Shared: Horror · Puzzle · Dark

Garten of Banban 2
Shared: Horror · Puzzle · First-Person

Phasmophobia
Shared: Horror · Psychological Horror · Dark

Mouthwashing
Shared: Horror · Retro · Psychological Horror

Outer Wilds
Shared: Exploration · Puzzle · Horror

Shipwrecked 64
Shared: Puzzle · Horror · Exploration

ANIMAL WELL
Shared: Puzzle · Exploration · Horror

DISTRAINT: Deluxe Edition
Shared: Horror · Pixel Graphics · Psychological Horror

Little Nightmares
Shared: Horror · Puzzle · Dark