In 1999 two teams moved from Dundee (dma-design) to Edinburgh. The team that had made Space Station Silicon Valley went on to make gta3.
The team that previously made 'Body Harvest' for the Nintendo 64 went on to work on Manhunt.
I was not directly involved with the game until the very end but here are some observations:
The design was mostly done by the team itself. The dark undertone was there from the start.
Initially there were some very ambitious ideas for the AI. The hunters were to be organized in groups of 4. The hunters would have a leader (sergeant) and the leaders would communicate with each other. The player would have a radio and be able to follow the conversations. If a hunter spotted the player, or something out-of-place, he would report this to his superior. Then the superior would make a decision on the course of action and give orders to his men as well as inform the other hunter groups. The AI could, for example, do a sweep of the room where the player was detected.
The level designers would only have to set up the hunters and their command structure. Then it would be a game of cat and mouse between the player and the hunters.
Unfortunately this never quite materialized. After 2 years, the programmer pushing the idea (and writing the AI) left the company and the idea was abandoned.
The game as it eventually shipped, contains a watered down version of these ideas. The player still has a radio and can still hear conversations, but it is scripted now and much of the hunter ai is too.
For a long time Manhunt used a first person perspective. This was at a time when many games were first person and 3rd person hadn't become the default yet. Manhunt in 1st person was a bit more immersive but moving around was a lot harder. It was hard to latch onto ladders for instance and when going up ladders you had no idea what was happening behind you. You could lean left/right with the shoulder buttons allowing you to look around corners. (Is that still there? not sure).
Quite late on during development, Leslie Benzies made the decision to switch to 3rd person. Everything got better.
Manhunt used Renderware (just like gta3) but they rendered their level using Binary Space Partitioning Trees (BSP). This is a great technique for indoor levels as it reduces the amount of overdraw (Rooms behind walls being rendered even though they're not visible). A problem with BSP's is that they take a long time to generate. Often the level artists had to let their computers process their level overnight. If there was only a tiny hole in the geometry anywhere, the BSP would be ruined and they would have to do it again.
During development there were quite a few design changes and technical problems. This made it hard for everyone but particularly the level designers. They didn't have a stable game to work with. For a long time the game would freeze for a second, every time a new hunter was created. This meant all hunters had to be created at the start of the level which isn't ideal.
It felt like Manhunt was stuck in development hell and it was hard going for the team. They kept at it though and eventually powered through to the other end of the tunnel.
For the last 2 months or so, half a dozen people from the gta team joined Manhunt to fix bugs and optimize. I also ported some of the visual fx I was working on at gta. That's why Manhunt has the same papers lying around everywhere, similar lens flares & pickups.
It was clear from the start that Manhunt was aiming for an 18/Mature certificate. Since this was the case, Rockstar New York was keen to emphasize and explore the dark themes.
The game was called Manhunt right from the start. At some point R*NY decided it sounded too much like a dating thing. The team and NY tried new names for several months but nothing better came up and it was back to the original name.
The game came together exceptionally well. The team had designed and implemented an atmospheric gem. It still has loads of fans today.
After Manhunt was done, the teams were merged. The Manhunters jumped from the chaos & stress of finishing their game, right into the chaos & stress of finishing SA.