Games like Save The Princess
Games like Save The Princess include SANABI, Anomaly Agent, Shovel Knight: Treasure Trove, Broforce, and Sonic Mania. We matched them by the tags players give Save The Princess on Steam (Side Scroller, 2D Platformer, Arcade, Platformer, and Action-Adventure): closest matches first, and among equally close ones the better-known games.

SANABI
Shared: 2D Platformer · Action · Pixel Graphics

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

Shovel Knight: Treasure Trove
Shared: Platformer · 2D · Pixel Graphics

Broforce
Shared: Action · Platformer · 2D

Sonic Mania
Shared: Platformer · 2D · Side Scroller

Sonic Origins
Shared: 2D Platformer · Action · Platformer

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

Super Meat Boy
Shared: Platformer · 2D Platformer · 2D

Rogue Legacy 2
Shared: Arcade · Platformer · Action

Mina the Hollower
Shared: Action-Adventure · 2D Platformer · Platformer

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

Rogue Legacy
Shared: Platformer · Action · 2D

Teenage Mutant Ninja Turtles: Shredder's Revenge
Shared: Side Scroller · Arcade · 2D

Blasphemous 2
Shared: 2D Platformer · Side Scroller · Pixel Graphics

Smilemo
Shared: Platformer · 2D Platformer · Side Scroller

Terminator 2D: NO FATE
Shared: Side Scroller · 2D Platformer · Arcade

Katana ZERO
Shared: Platformer · 2D Platformer · Action

Gravity Circuit
Shared: Platformer · Action · 2D Platformer

BlazBlue Entropy Effect
Shared: 2D · Platformer · Action-Adventure

Downwell
Shared: Platformer · Arcade · 2D Platformer

Celeste
Shared: 2D Platformer · Platformer · Pixel Graphics

The Messenger
Shared: Platformer · 2D · 2D Platformer

