Games like 8 Eyes
Games like 8 Eyes include Sonic Mania, Shovel Knight: Treasure Trove, Sonic Origins, SANABI, and Broforce. We matched them by the tags players give 8 Eyes on Steam (Action, Adventure, Retro, Platformer, and 2D): closest matches first, and among equally close ones the better-known games.

Sonic Mania
Shared: Retro · Platformer · 2D

Shovel Knight: Treasure Trove
Shared: Platformer · Retro · Adventure

Sonic Origins
Shared: Action · Adventure · Retro

SANABI
Shared: Action · Adventure · 2D

Broforce
Shared: Action · 2D · Platformer

Bloodstained: Curse of the Moon
Shared: Action · Retro · Platformer

DuckTales: Remastered
Shared: Adventure · Action · Platformer

Rayman® Legends
Shared: Adventure · Action · Platformer

Out There Somewhere
Shared: Platformer · Adventure · Action

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

The Messenger
Shared: Retro · Platformer · Action

Narita Boy
Shared: Action · Adventure · Retro

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

Hollow Knight
Shared: Platformer · 2D · Adventure

Dead Cells
Shared: Adventure · 2D · Platformer

Angry Video Game Nerd Adventures
Shared: Action · Platformer · Adventure

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

Gato Roboto
Shared: Action · Adventure · 2D

Sonic Adventure 2
Shared: Action · Platformer · Adventure

Castlevania Anniversary Collection
Shared: Action · Adventure · Platformer

Sonic Adventure DX
Shared: Platformer · Adventure · Action

Freedom Planet
Shared: Action · Platformer · 2D

Sonic the Hedgehog 4 Episode 1
Shared: Action · Platformer · Adventure

Volgarr the Viking
Shared: Action · Platformer · Retro