Games like The Sirena Expedition
Games like The Sirena Expedition include INSIDE, Little Nightmares, Subnautica, Oxenfree, and Firework. We matched them by the tags players give The Sirena Expedition on Steam (Horror, Platformer, Underwater, Atmospheric, and Supernatural): closest matches first, and among equally close ones the better-known games.

INSIDE
Shared: Horror · Atmospheric · 2.5D

Little Nightmares
Shared: Horror · Atmospheric · Adventure

Subnautica
Shared: Horror · Underwater · Adventure

Oxenfree
Shared: Atmospheric · Supernatural · Horror

Firework
Shared: Horror · Atmospheric · Indie

DreadOut
Shared: Horror · Atmospheric · Adventure

Iron Lung
Shared: Horror · Atmospheric · Underwater

Subnautica 2
Shared: Horror · Underwater · Atmospheric

GRIS
Shared: Atmospheric · Platformer · Adventure

Neva
Shared: Platformer · Atmospheric · Adventure

Little Nightmares II
Shared: Horror · Atmospheric · Adventure

The Mortuary Assistant
Shared: Horror · Supernatural · Atmospheric

Celeste
Shared: Platformer · 2D Platformer · Female Protagonist

Murdered: Soul Suspect
Shared: Horror · Supernatural · Atmospheric

No one lives under the lighthouse Director's cut
Shared: Horror · Atmospheric · Adventure

LIMBO
Shared: Platformer · Atmospheric · Horror

ANIMAL WELL
Shared: Platformer · Horror · Atmospheric

Hellblade: Senua's Sacrifice
Shared: Atmospheric · Horror · Female Protagonist

Hollow Knight
Shared: Platformer · Atmospheric · Adventure

Firewatch
Shared: Atmospheric · Adventure · Horror

Stray
Shared: Atmospheric · Adventure · Horror

Rain World
Shared: Atmospheric · Platformer · 2D Platformer

DREDGE
Shared: Atmospheric · Horror · Adventure

F.I.S.T.: Forged In Shadow Torch
Shared: Platformer · 2D Platformer · Adventure