Games like NightmareZ
Games like NightmareZ include Shovel Knight: Treasure Trove, Skul: The Hero Slayer, Super Meat Boy, Celeste, and Hollow Knight. We matched them by the tags players give NightmareZ on Steam (Action, Indie, Platformer, 2D, and Retro): closest matches first, and among equally close ones the better-known games.

Shovel Knight: Treasure Trove
Shared: Platformer · Indie · Retro

Skul: The Hero Slayer
Shared: Action · Indie · 2D

Super Meat Boy
Shared: Platformer · Indie · 2D

Celeste
Shared: Indie · Platformer · Pixel Graphics

Hollow Knight
Shared: Platformer · Indie · 2D

SANABI
Shared: Action · Pixel Graphics · Indie

Katana ZERO
Shared: Action · Platformer · Pixel Graphics

Hollow Knight: Silksong
Shared: Indie · 2D · Difficult

The Messenger
Shared: Platformer · Retro · 2D

Jump King
Shared: Indie · Platformer · Difficult

Broforce
Shared: Action · 2D · Platformer

Cuphead
Shared: Platformer · Difficult · 2D

Bloodstained: Curse of the Moon
Shared: Action · Platformer · Retro

Out There Somewhere
Shared: Platformer · Indie · Pixel Graphics

VVVVVV
Shared: Platformer · Indie · Pixel Graphics

Angry Video Game Nerd Adventures
Shared: Indie · Action · Platformer

Hotline Miami
Shared: Action · Indie · Pixel Graphics

Gravity Circuit
Shared: Action · Indie · Platformer

Pizza Tower
Shared: Indie · Platformer · Action

Axiom Verge
Shared: Indie · Platformer · Action

Geometry Dash
Shared: 2D · Difficult · Platformer

Gato Roboto
Shared: Indie · Action · 2D

Rogue Legacy
Shared: Platformer · Indie · Action

Freedom Planet
Shared: Action · Platformer · Indie