Games like Gastropod Alien Adventures
Games like Gastropod Alien Adventures include Rogue Legacy 2, Hollow Knight, SANABI, Hollow Knight: Silksong, and LIMBO. We matched them by the tags players give Gastropod Alien Adventures on Steam (Adventure, Action-Adventure, Arcade, Platformer, and Side Scroller): closest matches first, and among equally close ones the better-known games.

Rogue Legacy 2
Shared: Arcade · Platformer · Adventure

Hollow Knight
Shared: Platformer · 2D · Adventure

SANABI
Shared: Adventure · Action-Adventure · 2D

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

LIMBO
Shared: Platformer · Indie · Adventure

Shovel Knight: Treasure Trove
Shared: Platformer · Adventure · 2D

Mark of the Ninja
Shared: Platformer · Adventure · 2D

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

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

Monster Boy and the Cursed Kingdom
Shared: Adventure · Platformer · Indie

Geometry Dash
Shared: 2D · Platformer · Singleplayer

Zombotron
Shared: Adventure · 2D · Indie

Rogue Legacy
Shared: Platformer · Indie · 2D

Deadlight
Shared: Platformer · Adventure · Indie

BEEP
Shared: Adventure · Platformer · Indie

Sonic Mania
Shared: Platformer · 2D · Adventure

Dust: An Elysian Tail
Shared: Platformer · Adventure · Indie

Constance
Shared: Platformer · Action-Adventure · 2D

GRIS
Shared: Adventure · Indie · Platformer

Wonder Boy: The Dragon's Trap
Shared: Adventure · Platformer · Indie

Celeste
Shared: Platformer · Indie · Adventure

ICEY
Shared: Adventure · Side Scroller · Indie

8Doors: Arum's Afterlife Adventure
Shared: Adventure · Action-Adventure · Platformer

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