Games like Protocol Aftertime
Games like Protocol Aftertime include Portal, Portal 2, LIMBO, Little Nightmares, and The Talos Principle 2. We matched them by the tags players give Protocol Aftertime on Steam (3D Platformer, Puzzle, Third Person, Atmospheric, and Platformer): closest matches first, and among equally close ones the better-known games.

Portal
Shared: Puzzle · 3D Platformer · Puzzle Platformer

Portal 2
Shared: Puzzle · Platformer · 3D Platformer

LIMBO
Shared: Puzzle · Puzzle Platformer · Platformer

Little Nightmares
Shared: Atmospheric · Puzzle · Puzzle Platformer

The Talos Principle 2
Shared: Puzzle · 3D Platformer · Puzzle Platformer

COCOON
Shared: Puzzle · Atmospheric · Puzzle Platformer

The Pedestrian
Shared: Puzzle · Puzzle Platformer · Platformer

Shady Part of Me
Shared: Puzzle · Atmospheric · Platformer

The Last Campfire
Shared: Puzzle · Atmospheric · 3D Platformer

Stray
Shared: Atmospheric · Puzzle · Third Person

A Story About My Uncle
Shared: Atmospheric · 3D Platformer · Platformer

Contrast
Shared: Puzzle · Platformer · Atmospheric

Papo & Yo
Shared: 3D Platformer · Puzzle · Puzzle Platformer

Legacy of Kain™ Soul Reaver 1&2 Remastered
Shared: Third Person · Puzzle · Platformer

Hypogea
Shared: 3D Platformer · Atmospheric · Third Person

INSIDE
Shared: Atmospheric · Puzzle Platformer · Puzzle

Tiny and Big: Grandpas Leftovers
Shared: Puzzle · 3D Platformer · Platformer

Braid
Shared: Puzzle · Puzzle Platformer · Platformer

Little Nightmares II
Shared: Puzzle · Atmospheric · Adventure

Seen
Shared: Puzzle · Atmospheric · Platformer

GRIS
Shared: Atmospheric · Platformer · Puzzle

Spirit of the North
Shared: Atmospheric · Puzzle · 3D Platformer

Tinykin
Shared: 3D Platformer · Puzzle · Third Person

Planet of Lana
Shared: Atmospheric · Puzzle · Puzzle Platformer