Equilibrium is a mission which I think has a certain degree of prestige within the community, so much so that I had no idea it was from only 2000 (Though admittedly late 2000). This is one of those missions which feels so different to everything else around it, that it honestly is mindblowing.

Equilibrium is about 5 rogue keepers trying to kill garrett. It is a puzzle mission, with 5 enemies searching for you while you try to solve it. However what makes this mission so unique is how those enemies work. Their behaviour is genuinely unpredictable, they speed up,slow down, and stop, seemingly at random, while also sharing garretts ability to hide in shadows, they will even switch weapons based on how far away you are. All this comes together to make them a genuine threat, even to an experienced thief player.

The actual puzzle itself is very straight forward, and I won't spoil it here, but gameplay wise, it is about finding books, and reading them. How does Garrett know which books in the library are needed? I guess it was part of his keeper training. I admit it's not the most engaging setup, but the gimmick of the mission more than makes up for it. The actual architecture of the abandonned library is pretty impressive, with some nice details and some cool locations, and the plot is servicable, if a bit thin.

Despite my high praise, the mission has three main issues that might ruin your enjoyment. First of all, some people might find it is extremely difficult to complete due to how tough and unpredictable the AI is in this mission. Trying to run around like you can in most FMs will be harshly punished by running headfirst into a stationary keeper.
Second of all, one of the objectives is to steal an items off each of the keepers. While this is very difficult it also, in my opinion, really highlights the more annoying aspects of these enemies, and ironically, with each pickpocket, I felt significantly less scared. These are foes that are at their best when you don't have a good understanding of how they work, but getting close enough to pickpocket them is likely to involve actively working out their patterns and in doing so, ruining the illusion somewhat.
But the biggest issue is that the books you read, remain on the shelf, and as a result, you pretty much must either use your notes page, or an external notepad, to remember the information you need. This, in my case, means alt-tabbing out of the game to copy down each readable, and is less than ideal.

There are also some roombrushing and flowbrushing issues, but that's all fairly minor in my opinion.

IF you are willing to deal with the difficuilty, this missions offers something truly unique to the player. The feeling of meeting an enemy that at times, feels like it's actually got some intelligence behind it (Even if it's mostly fake) is really refreshing, and there is a reason why this mission is still occasionally talked about to this day.

If you haven't played this mission yet, I firmly recommend you give it a try.