Games like Instant Death
Games like Instant Death include Clustertruck, Getting Over It with Bennett Foddy, Ultimate Custom Night, A Story About My Uncle, and Outlast. We matched them by the tags players give Instant Death on Steam (Casual, Action, Indie, Difficult, and 3D Platformer): closest matches first, and among equally close ones the better-known games.

Clustertruck
Shared: Action · Parkour · 3D Platformer

Getting Over It with Bennett Foddy
Shared: Difficult · Psychological Horror · Indie

Ultimate Custom Night
Shared: Difficult · Singleplayer · First-Person

A Story About My Uncle
Shared: Indie · Parkour · First-Person

Outlast
Shared: First-Person · Psychological Horror · Survival Horror

Five Nights at Freddy's 3
Shared: Difficult · Indie · Singleplayer

Gorilla Tag
Shared: Psychological Horror · Parkour · First-Person

FIVE NIGHTS AT FREDDY'S: HELP WANTED
Shared: Action · Singleplayer · First-Person

Five Nights at Freddy's 2
Shared: Difficult · Indie · Singleplayer

Five Nights at Freddy's
Shared: Indie · Difficult · Singleplayer

Geometry Dash
Shared: Difficult · Indie · Singleplayer

Five Nights at Freddy's 4
Shared: Difficult · First-Person · Singleplayer

Dead Bits
Shared: Action · Casual · Indie

Refunct
Shared: 3D Platformer · Parkour · Casual

Five Nights at Freddy's: Sister Location
Shared: Difficult · First-Person · Singleplayer

Hollow Knight: Silksong
Shared: Indie · Difficult · Singleplayer

Neon White
Shared: 3D Platformer · Action · Parkour

Sword With Sauce
Shared: Action · Parkour · First-Person

SUPERHOT
Shared: Action · Indie · First-Person

DeadCore
Shared: Action · Indie · Difficult

A Dance of Fire and Ice
Shared: Difficult · Indie · Singleplayer

Valley
Shared: Indie · Action · First-Person

Ben and Ed
Shared: Action · Parkour · 3D Platformer

Super Hexagon
Shared: Difficult · Indie · Action