The third game in the Thief series, "Deadly Shadows" has done a good job of keeping the traditions and gameplay style that made the earlier games so great. While there are some new features, much of the game has been kept the same as its predecessors.
The game once again follows Garret, the eponymous thief, as he goes about stealing from particularly rich and wealthy victims. The game takes place in a fantasy medieval world, so in addition to guards and thugs of a more mundane variety there are also zombies, ghosts, various types of golem, and magical items.
The game uses a first-person camera and focuses on stealth. The missions take place at night, so sticking to the shadows (hence the name of the game) and moving quietly are key. Guards will often stand near lanterns or hold torches, so approaching them from a spot where they can't see you is important. Garret has many tools that he can use on his mission, both magical and mundane. His melee weapons are the non-lethal blackjack and the dagger. His ranged weapons are much more diverse - apart from regular, deadly arrows, Garret can purchase water arrows (which extinguish lights), moss arrows (which can be used to soften otherwise loud surfaces), gas arrows (launches knockout gas), fire arrows (highly damaging, but also highly visible), and noisemaker arrows (make noise when they hit, and are used to distract guards). In addition to these, Garret also has many kinds of mines and grenades as well.
Like the other games, Garret has many missions with various objectives, usually involving sneaking somewhere and stealing something. However, the ability to move around the city itself - instead of going from mission to mission like in old games - has been added. It's also possible to earn favor with either the Hammerites (a technological-based religious order) or the Pagans (a nature-favoring group, representing chaos to the Hammerites' law).
The graphics are pretty good, especially in the field of lighting. With the brightness properly set (there is a test when you first play the game to ensure your lighting is right) the atmosphere is definitely set. Light flickers through bars and windows, and avoiding it is very important to the gameplay; thus, it is well rendered. The human forms are not quite as good, but to be fair it is dark most of the time. The sound is pretty good, but there isn't any music that I could notice (because, well, it's a stealth game).
As a whole, the game has done a good job of keeping the Thief franchise going. It's not particularly exceptional as its own game because it's continuing a tradition, but if you liked the other Thief games this one should not disappoint.