Games like Cosmic Ascension
Games like Cosmic Ascension include Risk of Rain Returns, Vampire Survivors, Deep Rock Galactic: Survivor, BALL x PIT, and Starship Troopers: Extermination. We matched them by the tags players give Cosmic Ascension on Steam (Action, Action Roguelike, Arcade, 2D, and Sci-fi): closest matches first, and among equally close ones the better-known games.

Risk of Rain Returns
Shared: Action Roguelike · 2D · Action

Vampire Survivors
Shared: Action Roguelike · 2D · Action

Deep Rock Galactic: Survivor
Shared: Action Roguelike · Action · PvE

BALL x PIT
Shared: Action · Arcade · Action Roguelike

Starship Troopers: Extermination
Shared: Action · Sci-fi · Combat

STAR WARS™ Battlefront™ II
Shared: Action · Space · Sci-fi

EVERSPACE™
Shared: Action Roguelike · Action · Space

HELLDIVERS™ 2
Shared: Action · PvE · Sci-fi

STAR WARS Jedi: Survivor™
Shared: Action · Singleplayer · Sci-fi

Dome Keeper
Shared: Action · Sci-fi · Singleplayer

Warhammer 40,000: Space Marine 2
Shared: Action · PvE · Sci-fi

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

BlazBlue Entropy Effect
Shared: Action Roguelike · Action · 2D

Windowkill
Shared: Action · Action Roguelike · Arcade

Have a Nice Death
Shared: Action Roguelike · 2D · Action

Rogue Legacy
Shared: Action Roguelike · Action · 2D

Nova Drift
Shared: Arcade · Action Roguelike · Action

Dead Space (2008)
Shared: Action · Sci-fi · Space

Project Lazarus
Shared: Action · Action Roguelike · Arcade

Mass Effect™ Legendary Edition
Shared: Sci-fi · Action · Space

Rogue: Genesia
Shared: Action Roguelike · Arcade · Action

Endless Sky
Shared: Space · Sci-fi · 2D

Halls of Torment
Shared: Action Roguelike · Action · Arcade

Brotato
Shared: Action Roguelike · Singleplayer · Sci-fi