Games like Hollow Floor
Games like Hollow Floor include Mouthwashing, Outlast, Still Wakes the Deep, SOMA, and Layers of Fear (2016). We matched them by the tags players give Hollow Floor on Steam (Horror, Surreal, Walking Simulator, Psychological Horror, and Adventure): closest matches first, and among equally close ones the better-known games.

Mouthwashing
Shared: Horror · Psychological Horror · Walking Simulator

Outlast
Shared: Horror · Psychological Horror · First-Person

Still Wakes the Deep
Shared: Horror · Psychological Horror · Walking Simulator

SOMA
Shared: Horror · Psychological Horror · Dark

Layers of Fear (2016)
Shared: Horror · Psychological Horror · Walking Simulator

Buckshot Roulette
Shared: Horror · Dark · First-Person

Endacopia
Shared: Horror · Psychological Horror · Surreal

The Exit 8
Shared: Horror · Walking Simulator · Psychological Horror

Visage
Shared: Horror · Psychological Horror · Dark

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

Eclipsium
Shared: Surreal · Walking Simulator · Psychological Horror

Scorn
Shared: Horror · First-Person · Psychological Horror

Amnesia: The Dark Descent
Shared: Horror · Psychological Horror · First-Person

Escape the Backrooms
Shared: Horror · Psychological Horror · First-Person

IMSCARED
Shared: Horror · Psychological Horror · Pixel Graphics

Poppy Playtime
Shared: Horror · First-Person · Psychological Horror

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

The Park®
Shared: Horror · Walking Simulator · Psychological Horror

Blair Witch
Shared: Horror · Psychological Horror · Adventure

Amnesia: A Machine For Pigs
Shared: Horror · Walking Simulator · Psychological Horror

Bad Parenting 1: Mr. Red Face
Shared: Horror · Walking Simulator · Psychological Horror

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

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

Fran Bow
Shared: Psychological Horror · Horror · Adventure