Humble StoreBest$3.49$9.99
-65%
PuzzleAdventure
The Subject: Protocol Zero — Best Price & Deals
Released: March 10, 2026
PC
Wait before buying The Subject: Protocol Zero — ThereAny Score 54/100, currently 253% above its all-time low.
Our take
Next major sale: Autumn Sale in 30 days
Turn on your camera. The Kessler Foundation is paying for your pain. The game uses your webcam and microphone, turning the room into a lab. Complete four stages: from the blink ban to the "Green Light, Red Light" game. Money or sanity? Be the first to complete Protocol Zero. If you dare.
The Subject: Protocol Zero has 2 active deals across Humble Store, GreenManGaming. The current lowest price is $3.49 on Humble Store — a 65% discount off the $9.99 retail price. Historical low: $2.91 (Oct 1, 2025). Compare prices on Steam, Epic Games Store, GOG, Fanatical, and more major PC game retailers below.
Original Price
$9.99
Current Price
$3.49
Lowest Price
$0.99
Jun 15, 2026
Last checked: just now