The best thing about PC gaming is that the classics don't die. They just don't. They remain timeless, immortal and ever-growing. To give a familiar example, Doom as it stands now is not the Doom of 1993, but something much deeper, broader and stranger.
While the Thief community may not be quite as massive, they are a dedicated lot. Case in point: Death's Cold Embrace, a winter-themed ten-mission campaign for Thief 2: The Metal Age, released just yesterday, a full 17 years since the game first came out.
Death's Cold Embrace requires the NewDark patch for Thief 2, which is semi-unofficial. I say semi, as it's handily integrated into the current GOG and Steam versions of the game. Impressively, they've gone the extra mile in making this campaign as international as possible, with German and French and Russian versions available already.
The need for the fan-upgraded engine is made clear in this screenshot gallery. While the game is still unmistakably Thief, there's a layer of spit and polish here just not seen in Looking Glass' original, with much more detailed architecture, textures and models than anything seen in the original game. The scale of the environments is no slouch either, with a lot of new ground to explore and rob.
One of the key selling points of Death's Cold Embrace is persistence; several missions are set in the same part of the city, with familiar streets and buildings revisited at different times as you progress through the campaign. While every mission is self contained (there's no branching storyline) there's plenty to explore, with old routes closing and new ones opening up. To further increase replay value, the location of objectives and complexity of puzzles increases on higher difficulty settings, so even returning thieves might have to improvise a little.