As a foundational main game released in 1998, Thief: The Dark Project is a first-person stealth simulator where you play Garrett, a master thief in a dark, Steampunk-inspired city. The core gameplay involves strictly avoiding detection by mastering light and shadow mechanics while navigating complex environments like haunted cathedrals and ruins. Success depends on using specialized tools, like water arrows, to manipulate guards and objectives, as direct combat is highly discouraged. The story centers on deception and revenge as you uncover hidden agendas through high-stakes thievery.
The game emphasizes resource management and environmental interaction. Players utilize a variety of specialized arrows—such as noisemakers, water arrows to douse torches, and moss arrows to silence footsteps—to manipulate the environment and distract guards. Movement is deliberate, incorporating crouching, leaning around corners, and careful footing to minimize noise.
The world is characterized by its oppressive, gothic ambiance. The city itself functions as a character, filled with forbidding prisons, opulent manors, and forgotten crypts. The narrative revolves around Garrett's involvement in thefts that pull him into a complex web of deception, revenge, and the hidden agendas of both his supposed allies and powerful enemies.
Its primary distinction lies in its uncompromising commitment to stealth simulation. The game actively punishes aggressive play, forcing players to think several steps ahead about patrol routes, sound propagation, and line-of-sight. The immersive first-person perspective, combined with the intricate level design, creates a palpable sense of tension and vulnerability that defined the genre for years to come.
This title is presented as the main game release. There are currently no officially released downloadable content packs or expansions associated with this specific version.
Medium level animated violence

I found some interesting info while raiding Monsegur's palace in Stonemarket. His ledger seemed to indicate the location of a very curious trinket stashed somewhere in a place called the Dark Hollow, itself located in Fidgewick's Hollow, a subdistrict of Downtowne. From what I've managed to gather by pushing my network of associates, the Dark Hollow is apparently some sort of very high-class brothel, and its exact location is very well hidden. Even Cutty doesn't know where it is exactly, and the man knows every place in The City. Looks like I'll have to do my own scouting. I'm pretty certain I'll find eager pockets ripe for picking inside the brothel, and if I can't manage that, there is always the neighborhood. The streets are cold and snow has fallen quite hard these past few days, so I don't think I'll find many people outside, though the local watchdogs are on the prowl for these Downwinder amateurs. I doubt they'd appreciate a sneak such as me wandering the streets and the cold rooftops, so I have to find that brothel quickly. I also doubt the guards will let me through uninvited so I better find a discreet way inside as well, and keep a low profile. I have no idea what I’ll find inside but I bet the place will be crowded and on high security... Let's just hope this chalice is worth it.

Thief Gold is a first-person perspective stealth game. It was the first game to use light and sound gameplay mechanics – different surfaces cause varying noise. You can use sound to your advantage - it's not only your main source of information on how close your enemies are but you can use it to distract them, for example by throwing objects. With unscripted levels, and objectives and paths altered based on difficulty settings, Thief Gold can give you hours of non-repetitive gameplay. This extended edition includes all of the missions from the first release, as well as three new missions adapted to the original storyline, with full voice acting and new graphics. It can still be considered the first game in the Thief series.