Games like A.R.E.S.: Extinction Agenda
Games like A.R.E.S.: Extinction Agenda include Skul: The Hero Slayer, Broforce, Hollow Knight, Rogue Legacy, and Intrusion 2. We matched them by the tags players give A.R.E.S.: Extinction Agenda on Steam (Action, Platformer, Indie, Side Scroller, and Sci-fi): closest matches first, and among equally close ones the better-known games.

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

Broforce
Shared: Action · Platformer · 2D

Hollow Knight
Shared: Platformer · Indie · 2D

Rogue Legacy
Shared: Platformer · Indie · Action

Intrusion 2
Shared: Action · Platformer · Indie

Rogue Legacy 2
Shared: Platformer · Action · Indie

My Friend Pedro
Shared: Action · Indie · Shooter

Zombotron
Shared: Action · Indie · 2D

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

Axiom Verge
Shared: Indie · Platformer · Action

Gravity Circuit
Shared: Action · Platformer · Indie

Defy Gravity Extended
Shared: Platformer · Indie · Action

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

Mark of the Ninja
Shared: Platformer · Indie · Action

BEEP
Shared: Platformer · Indie · Action

Gato Roboto
Shared: Action · Indie · Platformer

ICEY
Shared: Action · Side Scroller · Indie

Ghost 1.0
Shared: Action · Indie · Platformer

Nine Sols
Shared: Platformer · Action · 2D

Out There Somewhere
Shared: Platformer · Indie · Action

Deadlight
Shared: Platformer · Action · Indie

SteamWorld Dig
Shared: Platformer · Indie · Action

Shovel Knight: Treasure Trove
Shared: Platformer · Indie · Action

Shank
Shared: Action · Indie · Side Scroller