Games like Peerless Heart
Games like Peerless Heart include The Beginner's Guide, Eclipsium, Keeper, Hylics, and September 7th. We matched them by the tags players give Peerless Heart on Steam (Walking Simulator, Psychedelic, Stylized, 1990's, and Linear): closest matches first, and among equally close ones the better-known games.

The Beginner's Guide
Shared: Walking Simulator · Atmospheric · Abstract

Eclipsium
Shared: Walking Simulator · Psychedelic · Surreal

Keeper
Shared: Walking Simulator · Surreal · Psychedelic

Hylics
Shared: Psychedelic · Surreal · Abstract

September 7th
Shared: Walking Simulator · Simulation · Linear

Manifold Garden
Shared: Psychedelic · Surreal · Abstract

INDIKA
Shared: Psychedelic · Surreal · Psychological

Barbotine
Shared: 1990's · Surreal · Psychological

I'm counting to 6...
Shared: Walking Simulator · Simulation · Psychedelic

NaissanceE
Shared: Walking Simulator · Abstract · Atmospheric

Hypnospace Outlaw
Shared: 1990's · Simulation · Surreal

Before Your Eyes
Shared: Walking Simulator · Narrative · Psychological

April 24th
Shared: Walking Simulator · Simulation · Psychedelic

Superliminal
Shared: Surreal · Psychedelic · Psychological

Burden Street Station
Shared: 1990's · Stylized · Surreal

Millennium Dream
Shared: Walking Simulator · 1990's · Atmospheric

Summer of '58
Shared: Walking Simulator · Atmospheric · Psychological

Mouthwashing
Shared: Walking Simulator · Atmospheric · Psychological

Neyasnoe
Shared: Walking Simulator · Stylized · Simulation

Mixtape
Shared: Walking Simulator · 1990's · Narrative

Antichamber
Shared: Surreal · Abstract · Psychedelic

KARMA: The Dark World
Shared: Walking Simulator · Atmospheric · Psychedelic

Broken Reality
Shared: Walking Simulator · Surreal · 1990's

Viewfinder
Shared: Surreal · Abstract · Psychological