Games like Illuminascii
Games like Illuminascii include Counter-Strike 2, Ready or Not, KovaaK's, Blood and Bacon, and Gunfire Reborn. We matched them by the tags players give Illuminascii on Steam (Indie, Action, FPS, Memes, and Roguelike): closest matches first, and among equally close ones the better-known games.

Counter-Strike 2
Shared: FPS · Action · Shooter

Ready or Not
Shared: FPS · Shooter · Action

KovaaK's
Shared: Action · Indie · FPS

Blood and Bacon
Shared: Action · FPS · Shooter

Gunfire Reborn
Shared: FPS · Roguelike · Indie

Trepang2
Shared: FPS · Action · Shooter

Aimlabs
Shared: FPS · Action · Shooter

Black Mesa
Shared: FPS · Action · First-Person

DOOM
Shared: FPS · Action · Shooter

Left 4 Dead 2
Shared: FPS · Action · Shooter

SUPERHOT
Shared: Action · FPS · Indie

BPM: BULLETS PER MINUTE
Shared: FPS · Action · Indie

Receiver 2
Shared: FPS · Indie · Action

Bright Memory: Infinite
Shared: Action · Indie · FPS

Half-Life: Alyx
Shared: FPS · Action · Horror

Call of Duty®
Shared: FPS · Action · Shooter

Bright Memory
Shared: FPS · Action · First-Person

Half-Life 2
Shared: Action · FPS · First-Person

BioShock Infinite
Shared: Action · FPS · First-Person

Counter-Strike
Shared: Action · FPS · Shooter

HOLE
Shared: FPS · Indie · Action

Counter-Strike: Source
Shared: Action · FPS · Shooter

Receiver
Shared: Indie · FPS · Action

Devil Daggers
Shared: Indie · FPS · Action