Thief 2 prototype appears in yet another leak

While not quite on the same scale as Grand Theft Auto 6 or Diablo 4, another recent video game leak has provided an intriguing insight into one of the PC's most critically acclaimed games. Over the weekend, an unfinished prototype of Thief 2: The Metal Age appeared on the Internet.

The prototype is dated November 4, 1999, which is roughly five months before the game launched in March 2000. It was discovered and uploaded by a game preservation organisation called The Project Eclipse Team, then shared by the Twitter account of one of its members @Hwd405, as part of a much larger release of game prototypes from the late nineties and early 2000s.

An analysis of the prototype was subsequently provided by Romain Barrilliot, a level designer at Arkane Studios and a huge Thief fan. "It is, as you can imagine, an absolute treasure trove", Barrilliot wrote on Twitter. Every level featured in the final game is available to play in the prototype version, but their stages of completion vary wildly. Some, like the fifth level "Eavesdropping" and the final level "Sabotage at Soulforge" are barely started, while others, such as the game's famous bank heist, are on the cusp of being finished.

Feature-wise, the prototype doesn't diverge radically from the final version, but Barrilliot notes a few interesting differences. For example, he points out the second mission "Shipping and Receiving" had two buildings to explore in the retail version, but the prototype includes a third building that was ultimately cut. Barrilliot also notes that the police station from Framed "looks nothing like what's in the final version in terms of texturing". Some missions also have different names. The ninth mission "Trail of Blood" is named in the prototype as "Trace the Courier" – the same name as the previous mission. Meanwhile, Thief 2's most famous mission "Life of the Party" is at this point known as "An Unexpected Guest".

There are tons of other fun little details too, such as entire in-game documents that were cut from the release version, and the fact that the prototype uses objects from Looking Glass' sister-project System Shock 2 as placeholders for things like enemies and security cameras. It's well worth reading through the entire thread.

In the context of the other leaks that have occurred recently, however, the Thief 2 prototype shows two things. First, while leaks of in-development games can have negative consequences for those games, from causing grief for developers to actively hindering a game's creation, leaks can also have a positive effect, particularly when they are sufficiently chronologically removed from the game's active development. This is a fascinating slice of video game history with a lot to be learned on it, and the fact that it's appeared now means it can't hurt Thief 2's development.

Which leads neatly onto my second point. The prototype demonstrates the vast amount of work that happens in the final stages of a game's development. With just five months to go before release, not a single level of Thief 2 is finished, and several of them are barely started. It's a striking example of how late in the day in development video games come together, which is especially important to understand in when looking at an in-development game like Grand Theft Auto 6. To peek behind the curtain is to see the actors in various states of undress, and it's silly to then complain about that when it's you doing the peeking.

Correction: A previous version of this article incorrectly attributed the original sharing of the Thief prototype on Twitter to Romain Barrilliot. The prototype was released by the Project Eclipse Team, and originally shared on Twitter by @Hwd405.