Games like Manifest 99
Games like Manifest 99 include Journey, Hollow Knight: Silksong, A Short Hike, Dream, and Firewatch. We matched them by the tags players give Manifest 99 on Steam (Indie, Exploration, Casual, and Walking Simulator): closest matches first, and among equally close ones the better-known games.

Journey
Shared: Indie · Exploration · Great Soundtrack

Hollow Knight: Silksong
Shared: Indie · Great Soundtrack · Exploration

A Short Hike
Shared: Indie · Exploration · Casual

Dream
Shared: Indie · Exploration · VR

Firewatch
Shared: Walking Simulator · Exploration · Indie

ABZU
Shared: Great Soundtrack · Exploration · Indie

Everybody's Gone to the Rapture
Shared: Indie · Great Soundtrack · Walking Simulator

Gone Home
Shared: Indie · Walking Simulator · Exploration

FEZ
Shared: Indie · Great Soundtrack · Exploration

Hollow Knight
Shared: Great Soundtrack · Indie · Exploration

What Remains of Edith Finch
Shared: Walking Simulator · Exploration · Indie

Proteus
Shared: Indie · Exploration · Walking Simulator

Deer Man
Shared: Indie · Exploration · Casual

OneShot
Shared: Indie · Great Soundtrack · Exploration

Outer Wilds
Shared: Exploration · Great Soundtrack · Indie

Scanner Sombre
Shared: Exploration · Walking Simulator · Indie

GRIS
Shared: Great Soundtrack · Indie · Casual

Obduction
Shared: Indie · Exploration · VR

Treasure Hunter Simulator
Shared: Indie · Exploration · Casual

The Stanley Parable
Shared: Indie · Walking Simulator · Exploration

Mountain
Shared: Indie · Casual · Great Soundtrack

Drizzlepath
Shared: Indie · Casual · Exploration

The First Tree
Shared: Indie · Exploration · Walking Simulator

AER Memories of Old
Shared: Indie · Exploration · Great Soundtrack