Thief: Deadly Shadows for mobile phones was divided into two episodes each containing eight missions. It follows the story line of the PC/console version but differs in that it is a side-scrolling 2D platforming game. The focus on stealth is still intact though and like in the original series Garrett's main objective of each mission is to steal specific items and a certain amount of loot. To succeed in sneaking past the guards, Garrett has to avoid bright light and hide in the shadows where he can not be seen. If spotted, civilians will alert nearby guards who will immediately draw their swords and attack. Like in previous Thief games there is a light gem in the HUD that shows how much light there is at the current location.
When getting close to a guard or civilian, Garrett can pick their pockets or attempt to knock them out with his blackjack. By doing this the player can retrieve important items and vital information, sometimes necessary to complete the mission. A knocked out body can be picked up and carried away which can be necessary since a spotted body will raise the alarm. In addition to the blackjack the player has access to some other items. There are three types of arrows; water for extinguishing torches, noise maker for distracting and broadheads for knocking targets. There are also two kinds of bombs: flash bombs that temporarily blind enemies and gas bombs that releases poisonous gas that knocks out enemies. Other items include health potions and a mechanical eye that can be used to scan further ahead into the level.
Between regular missions there are rooftop levels where Garrett has to escape from the scene of crime. These are action sequences that work similar to endless runner games where Garrett moves forward and the player has to jump at the right time to avoid falling. Once the rooftop level is completed the player will get to a shop where loot can be sold and new items can be bought.