Games like Duet
Games like Duet include Super Hexagon, Hollow Knight: Silksong, Geometry Dash, A Dance of Fire and Ice, and Hollow Knight. We matched them by the tags players give Duet on Steam (Indie, Action, Minimalist, Difficult, and Casual): closest matches first, and among equally close ones the better-known games.

Super Hexagon
Shared: Indie · Difficult · Great Soundtrack

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

Geometry Dash
Shared: Difficult · Great Soundtrack · 2D

A Dance of Fire and Ice
Shared: Difficult · Indie · Singleplayer

Hollow Knight
Shared: Difficult · Indie · Great Soundtrack

Baba Is You
Shared: Indie · Difficult · Puzzle

Zup! S
Shared: Indie · Casual · Puzzle

Just Shapes & Beats
Shared: Great Soundtrack · Difficult · Indie

Celeste
Shared: Difficult · Indie · Great Soundtrack

Hyper Light Drifter
Shared: Indie · Great Soundtrack · Action

Hotline Miami
Shared: Action · Indie · Great Soundtrack

The Binding of Isaac: Rebirth
Shared: Indie · Difficult · Great Soundtrack

Waveform
Shared: Indie · Great Soundtrack · Casual

Hexcells
Shared: Indie · Casual · Minimalist

Muse Dash
Shared: Great Soundtrack · Rhythm · Casual

Hook
Shared: Minimalist · Casual · Puzzle

LIMBO
Shared: Indie · Puzzle · Singleplayer

Defy Gravity Extended
Shared: Indie · Action · Puzzle

140
Shared: Indie · Minimalist · Great Soundtrack

SUPERHOT
Shared: Action · Indie · Singleplayer

Hotline Miami 2: Wrong Number
Shared: Great Soundtrack · Action · Difficult

Zenge
Shared: Indie · Minimalist · Casual

Minimalism
Shared: Indie · Action · Difficult

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