Games like Porter in the Castle
Games like Porter in the Castle include Dust: An Elysian Tail, Rogue Legacy 2, Caster, Bloodstained: Ritual of the Night, and Brawlhalla. We matched them by the tags players give Porter in the Castle on Steam (Action, Adventure, Casual, RPG, and Strategy): closest matches first, and among equally close ones the better-known games.

Dust: An Elysian Tail
Shared: Action · Adventure · RPG

Rogue Legacy 2
Shared: Action · Adventure · Platformer

Caster
Shared: Action · Adventure · Casual

Bloodstained: Ritual of the Night
Shared: Action · RPG · Adventure

Brawlhalla
Shared: Casual · 2D Fighter · Action

Dead Cells
Shared: Adventure · Roguelike · Action

UFO 50
Shared: Action · Adventure · Strategy

Rogue Legacy
Shared: Action · Platformer · Roguelike

Juicy Realm
Shared: Action · Adventure · RPG

SMITE 2
Shared: Action · Adventure · Strategy

Ori and the Will of the Wisps
Shared: Action · Adventure · Platformer

F.I.S.T.: Forged In Shadow Torch
Shared: Action · Adventure · Platformer

UnEpic
Shared: RPG · Action · Platformer

Plebby Quest: The Crusades
Shared: Casual · Strategy · RPG

Skul: The Hero Slayer
Shared: Action · Roguelike · Platformer

Hollow Knight
Shared: Platformer · Adventure · Metroidvania

Vampire Survivors
Shared: Casual · Bullet Hell · Action

Fallout 4
Shared: Adventure · RPG · Action

Minishoot' Adventures
Shared: Adventure · RPG · Casual

Dead Age
Shared: RPG · Strategy · Adventure

Sonic Origins
Shared: Action · Adventure · Casual

BEEP
Shared: Adventure · Platformer · Action

Escape From Duckov
Shared: Action · Adventure · Shooter

Eastern Exorcist
Shared: Action · RPG · Adventure