Games like The Music Machine
Games like The Music Machine include Firewatch, What Remains of Edith Finch, Layers of Fear (2016), Poppy Playtime, and Little Nightmares. We matched them by the tags players give The Music Machine on Steam (Adventure, Indie, Horror, First-Person, and Walking Simulator): closest matches first, and among equally close ones the better-known games.

Firewatch
Shared: Adventure · Walking Simulator · First-Person

What Remains of Edith Finch
Shared: Walking Simulator · Adventure · First-Person

Layers of Fear (2016)
Shared: Horror · First-Person · Walking Simulator

Poppy Playtime
Shared: Horror · First-Person · Singleplayer

Little Nightmares
Shared: Adventure · Horror · Indie

Outlast
Shared: Horror · First-Person · Psychological Horror

SOMA
Shared: Horror · Psychological Horror · Atmospheric

Outer Wilds
Shared: Adventure · Exploration · Indie

Amnesia: A Machine For Pigs
Shared: Horror · Walking Simulator · First-Person

Little Nightmares II
Shared: Adventure · Horror · Singleplayer

Among the Sleep - Enhanced Edition
Shared: Indie · Horror · Adventure

Blair Witch
Shared: Adventure · Horror · Indie

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

Visage
Shared: Horror · Psychological Horror · First-Person

Scanner Sombre
Shared: Horror · Adventure · Walking Simulator

Slender: The Arrival
Shared: Horror · Indie · First-Person

INFRA
Shared: Adventure · Exploration · First-Person

IMSCARED
Shared: Indie · Horror · Adventure

Lethal Company
Shared: Horror · First-Person · Exploration

ROUTINE
Shared: Adventure · Psychological Horror · Horror

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

The Park®
Shared: Horror · First-Person · Walking Simulator

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