Games like Water Delivery
Games like Water Delivery include Firewatch, What Remains of Edith Finch, No, I'm not a Human, Poppy Playtime, and Layers of Fear (2016). We matched them by the tags players give Water Delivery on Steam (Adventure, Horror, Mystery, Psychological Horror, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Firewatch
Shared: Adventure · Atmospheric · Mystery

What Remains of Edith Finch
Shared: Mystery · Atmospheric · Adventure

No, I'm not a Human
Shared: Horror · Psychological Horror · Atmospheric

Poppy Playtime
Shared: Horror · Singleplayer · First-Person

Layers of Fear (2016)
Shared: Horror · Psychological Horror · Atmospheric

Sally Face - Episode One
Shared: Horror · Psychological Horror · Adventure

Outlast
Shared: Horror · Psychological Horror · Atmospheric

SOMA
Shared: Horror · Psychological Horror · Atmospheric

The Mortuary Assistant
Shared: Horror · Mystery · Atmospheric

Amnesia: A Machine For Pigs
Shared: Horror · Atmospheric · Psychological Horror

MiSide
Shared: Psychological Horror · Horror · First-Person

Little Nightmares II
Shared: Adventure · Horror · Atmospheric

Little Nightmares
Shared: Horror · Adventure · Atmospheric

Mouthwashing
Shared: Horror · Psychological Horror · Atmospheric

Oxenfree
Shared: Atmospheric · Adventure · Mystery

Visage
Shared: Horror · Psychological Horror · Adventure

Outer Wilds
Shared: Mystery · Adventure · Atmospheric

Blair Witch
Shared: Adventure · Horror · Psychological Horror

Outlast 2
Shared: Horror · Psychological Horror · First-Person

Still Wakes the Deep
Shared: Horror · Psychological Horror · First-Person

Phasmophobia
Shared: Horror · Psychological Horror · First-Person

The Test
Shared: Simulation · Psychological Horror · Multiple Endings

The Room Two
Shared: Mystery · Horror · Adventure

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