Games like Niji Protocol
Games like Niji Protocol include Murders on the Yangtze River, Phoenix Wright: Ace Attorney Trilogy, The Painscreek Killings, Danganronpa: Trigger Happy Havoc, and Strange Horticulture. We matched them by the tags players give Niji Protocol on Steam (Detective, Investigation, Trivia, Education, and Puzzle): closest matches first, and among equally close ones the better-known games.

Murders on the Yangtze River
Shared: Detective · Puzzle · Investigation

Phoenix Wright: Ace Attorney Trilogy
Shared: Detective · Mystery · Visual Novel

The Painscreek Killings
Shared: Investigation · Detective · Mystery

Danganronpa: Trigger Happy Havoc
Shared: Detective · Visual Novel · Mystery

Strange Horticulture
Shared: Detective · Puzzle · Mystery

Staffer Case: A Supernatural Mystery Adventure
Shared: Detective · Mystery · Visual Novel

Tangle Tower
Shared: Detective · Puzzle · Exploration

Danganronpa 2: Goodbye Despair
Shared: Detective · Mystery · Visual Novel

Sanfu
Shared: Puzzle · Mystery · Visual Novel

The Rise of the Golden Idol
Shared: Investigation · Detective · Mystery

The Case of the Golden Idol
Shared: Detective · Investigation · Mystery

No Case Should Remain Unsolved
Shared: Investigation · Puzzle · Visual Novel

Blue Prince
Shared: Investigation · Puzzle · Exploration

The Roottrees are Dead
Shared: Detective · Investigation · Puzzle

The Incident at Galley House
Shared: Detective · Puzzle · Mystery

Sherlock Holmes: Crimes and Punishments
Shared: Detective · Investigation · Mystery

Cyber Manhunt 2: New World - The Hacking Simulator
Shared: Detective · Investigation · Puzzle

Sherlock Holmes: The Devil's Daughter
Shared: Detective · Puzzle · Mystery

Her Story
Shared: Investigation · Detective · Puzzle

Duck Detective: The Secret Salami
Shared: Detective · Investigation · Casual

Strange Antiquities
Shared: Detective · Puzzle · Mystery

Danganronpa V3: Killing Harmony
Shared: Detective · Visual Novel · Mystery

Return of the Obra Dinn
Shared: Detective · Puzzle · Mystery

Demons' Timeline
Shared: Detective · Investigation · Mystery