Thief is a reboot of the Thief series, discarding most of its lore. The game follows Garrett, a master thief, who teams up with his former apprentice Erin on a job that goes wrong. They stumble upon a mysterious ritual from a faction similar to the Mechanists, and Erin gets caught in the middle. When Garrett awakens after a year, he finds himself in a fascist regime with people affected by a strange disease. His goal is to uncover the truth and stop the conspiracy. The gameplay structure is similar to Deadly Shadows . The city hub is divided into districts, which open up gradually as you progress through the game. You can explore these areas freely until starting a mission. The main difference from previous games is the modular design of levels, which are more like clockwork mechanisms with choke-points leading to the next area. Movement is restricted, and Garrett uses his wits to overcome obstacles.
The gameplay focuses on stealth, using shadows to stay hidden. Garrett can take on guards in combat, but stealth is his preferred method. He uses contextual button presses to dodge attacks and place blackjack hits at the right moments. The system rewards careful observation of guard patrols, timing your movements carefully to avoid detection.
Throughout the game, you'll find loot by exploring the city, completing side missions, or visiting shops. Side missions reward valuable equipment and unique items hidden within paintings, books, or safes. You'll need to use a new mechanic, "switching" switches, to access these secrets. The lockpicking minigame requires finding the sweet spot by moving the lockpick around.
Between missions, Garrett can find additional loot, and optional side missions offer lucrative opportunities for quick burglaries or self-contained missions. Visiting shops allows you to stock up on equipment, such as arrows, food items, or smoke bombs. You can also purchase one-time upgrades or special abilities, like a swoop move or focus.
The game features several difficulty modes, including options to disable certain mechanics or increase the challenge. The PlayStation 4 version uses the DualShock 4's light bar to emphasize the effect of being in the shadows or exposed to light.
Besides the main campaign, there is a challenge mode that reuses mission areas with special objectives. The goal is to achieve high scores on leaderboards by completing these challenges within time limits.