Games like Melon Knight
Games like Melon Knight include Undertale, OneShot, To the Moon, SANABI, and Papers, Please. We matched them by the tags players give Melon Knight on Steam (Minimalist, Choices Matter, Story Rich, Retro, and Pixel Graphics): closest matches first, and among equally close ones the better-known games.

Undertale
Shared: Choices Matter · Story Rich · Pixel Graphics

OneShot
Shared: Story Rich · Pixel Graphics · Choices Matter

To the Moon
Shared: Story Rich · Pixel Graphics · Singleplayer

SANABI
Shared: Story Rich · Pixel Graphics · Singleplayer

Papers, Please
Shared: Pixel Graphics · Singleplayer · Story Rich

DELTARUNE
Shared: Story Rich · Pixel Graphics · Singleplayer

Detroit: Become Human
Shared: Choices Matter · Story Rich · Singleplayer

Dispatch
Shared: Choices Matter · Story Rich · Singleplayer

Finding Paradise
Shared: Story Rich · Pixel Graphics · 2D

The Witcher 3: Wild Hunt — Remastered
Shared: Story Rich · Choices Matter · Singleplayer

DAVE THE DIVER
Shared: Pixel Graphics · Adventure · Casual

Yes, Your Grace
Shared: Choices Matter · Pixel Graphics · Story Rich

Dead Cells
Shared: Adventure · Pixel Graphics · 2D

There Is No Game: Wrong Dimension
Shared: Pixel Graphics · Adventure · Story Rich

Vampire Survivors
Shared: Pixel Graphics · 2D · Singleplayer

The Test
Shared: Story Rich · Pixel Graphics · Choices Matter

A Bird Story
Shared: Story Rich · Pixel Graphics · Singleplayer

Impostor Factory
Shared: Story Rich · Pixel Graphics · 2D

Emily is Away Too
Shared: Choices Matter · Story Rich · Pixel Graphics

The Red Strings Club
Shared: Story Rich · Choices Matter · Pixel Graphics

Balatro
Shared: Singleplayer · Pixel Graphics · Roguelike

The Binding of Isaac: Rebirth
Shared: Pixel Graphics · Roguelike · Replay Value

Beat Cop
Shared: Pixel Graphics · Retro · Adventure

The Wolf Among Us
Shared: Story Rich · Choices Matter · Adventure