Stealth Bastard Deluxe is the commercial version of the free prototype Stealth Bastard: Tactical Espionage Arsehole. Just like the original title it is a platform game based around stealth. The player controls a clone inside a facility and needs to complete levels by remaining undetected. Cameras and robots with lasers can generally be avoided by staying in the shadows. The clone's goggles are green when it is safe, but they turn red when in danger and that usually leads to instant death. There are blind hunters who only react to sounds and levels filled with floors that produce noise when pressured. Just like titles as Super Meat Boy levels are generally not meant to be completed in a single go, but require multiple tries to figure out the patterns.
The puzzle elements require quick timing and the manipulation of switches, teleporters and doors, along with platform jumping and pushing objects. Terminals can be hacked to progress, but this takes time and often requires the clone to lure a sentry away. This version introduces new types of gadgets such as a camouflage suite (limited, charged invisibility), deploying a regular decoy or a sonic decoy, antilight and teleporters. The 28 version of the original game are replaced by 80 levels that are entirely new. They are set inside a facility divided into distinct areas. Just like the original game a level editor is included to create and share levels. Custom levels created with the original version are carried over.