Games like Alchemist's Castle
Games like Alchemist's Castle include Hollow Knight, Shovel Knight: Treasure Trove, Hollow Knight: Silksong, Axiom Verge, and Skul: The Hero Slayer. We matched them by the tags players give Alchemist's Castle on Steam (Indie, Action, Adventure, Metroidvania, and 2D): closest matches first, and among equally close ones the better-known games.

Hollow Knight
Shared: Metroidvania · Indie · 2D

Shovel Knight: Treasure Trove
Shared: Indie · Retro · Pixel Graphics

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

Axiom Verge
Shared: Indie · Metroidvania · Action

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

Gato Roboto
Shared: Indie · Action · Metroidvania

The Messenger
Shared: Metroidvania · Retro · Indie

SANABI
Shared: Action · Pixel Graphics · Adventure

Out There Somewhere
Shared: Indie · Adventure · Pixel Graphics

Dust: An Elysian Tail
Shared: Action · Indie · Metroidvania

Bloodstained: Curse of the Moon
Shared: Action · Retro · Pixel Graphics

Iconoclasts
Shared: Indie · Metroidvania · Action

Blasphemous
Shared: Metroidvania · Indie · Pixel Graphics

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

Celeste
Shared: Indie · Pixel Graphics · Great Soundtrack

Sonic Mania
Shared: 2D · Retro · Great Soundtrack

Dead Cells
Shared: Adventure · Metroidvania · 2D

Broforce
Shared: Action · 2D · Pixel Graphics

CARRION
Shared: Action · Metroidvania · Indie

ICEY
Shared: Action · Indie · Adventure

MO:Astray
Shared: Indie · Action · Adventure

Rogue Legacy 2
Shared: Action · Metroidvania · Indie

Katana ZERO
Shared: Action · Pixel Graphics · Indie

Owlboy
Shared: Indie · Adventure · Pixel Graphics