Games like ECHOPLEX
Games like ECHOPLEX include The Talos Principle, Half-Life 2, Deliver Us The Moon, Outer Wilds, and Black Mesa. We matched them by the tags players give ECHOPLEX on Steam (Indie, Action, Simulation, Adventure, and Puzzle): closest matches first, and among equally close ones the better-known games.

The Talos Principle
Shared: Puzzle · Sci-fi · First-Person

Half-Life 2
Shared: Action · Sci-fi · Adventure

Deliver Us The Moon
Shared: Indie · Action · Adventure

Outer Wilds
Shared: Adventure · Story Rich · Puzzle

Black Mesa
Shared: Action · Sci-fi · First-Person

Brothers - A Tale of Two Sons
Shared: Adventure · Indie · Story Rich

OneShot
Shared: Indie · Story Rich · Puzzle

A Story About My Uncle
Shared: Adventure · Indie · First-Person

BioShock Infinite
Shared: Action · First-Person · Adventure

The Beginner's Guide
Shared: Indie · Story Rich · First-Person

Seen
Shared: Indie · Adventure · Puzzle

Firewatch
Shared: Adventure · Story Rich · Indie

Antichamber
Shared: Indie · Puzzle · First-Person

Return of the Obra Dinn
Shared: Puzzle · Indie · Story Rich

Ori and the Will of the Wisps
Shared: Action · Adventure · Great Soundtrack

Papers, Please
Shared: Indie · Simulation · Puzzle

Portal 2
Shared: Puzzle · First-Person · Story Rich

Q.U.B.E. 2
Shared: Action · Indie · Adventure

What Remains of Edith Finch
Shared: Story Rich · Adventure · First-Person

Valley
Shared: Adventure · Indie · Action

Bendy and the Dark Revival
Shared: Action · Indie · Adventure

BONEWORKS
Shared: Action · Puzzle · Adventure

GRIS
Shared: Indie · Adventure · Great Soundtrack

Portal
Shared: Puzzle · First-Person · Sci-fi