Games like Pixel Ninja
Games like Pixel Ninja include Lost Castle, Anomaly Agent, Skul: The Hero Slayer, SYNTHETIK: Legion Rising, and Vampire Survivors. We matched them by the tags players give Pixel Ninja on Steam (Action Roguelike, Side Scroller, Spectacle fighter, 2D Platformer, and Top-Down Shooter): closest matches first, and among equally close ones the better-known games.

Lost Castle
Shared: Action Roguelike · Side Scroller · Beat 'em up

Anomaly Agent
Shared: Side Scroller · Action Roguelike · 2D Platformer

Skul: The Hero Slayer
Shared: Action Roguelike · Roguelite · Side Scroller

SYNTHETIK: Legion Rising
Shared: Action Roguelike · Top-Down Shooter · Roguelite

Vampire Survivors
Shared: Action Roguelike · Roguelite · Indie

Hades
Shared: Action Roguelike · Roguelite · Indie

20XX
Shared: Action Roguelike · 2D Platformer · Roguelite

Nuclear Throne
Shared: Action Roguelike · Roguelite · Top-Down Shooter

Risk of Rain 2
Shared: Action Roguelike · Roguelite · Action

Brawlhalla
Shared: Free to Play · 2D Platformer · Casual

30XX
Shared: Action Roguelike · Side Scroller · 2D Platformer

20 Minutes Till Dawn
Shared: Action Roguelike · Roguelite · Top-Down Shooter

暖雪 Warm Snow
Shared: Action Roguelike · Roguelite · Martial Arts

Tiny Rogues
Shared: Action Roguelike · Top-Down Shooter · Roguelite

Momodora: Reverie Under The Moonlight
Shared: Side Scroller · 2D Platformer · Spectacle fighter

Dungreed
Shared: Action Roguelike · Roguelite · Side Scroller

The Binding of Isaac
Shared: Action Roguelike · Indie · Difficult

SNKRX
Shared: Action Roguelike · Roguelite · Top-Down Shooter

Realm of the Mad God Exalt
Shared: Action Roguelike · Free to Play · Roguelite

Deep Rock Galactic: Survivor
Shared: Action Roguelike · Roguelite · Top-Down Shooter

BALL x PIT
Shared: Action Roguelike · Roguelite · Top-Down Shooter

The Binding of Isaac: Rebirth
Shared: Action Roguelike · Indie · Difficult

Megabonk
Shared: Action Roguelike · Roguelite · Indie

Absolum
Shared: Roguelite · Beat 'em up · Side Scroller