Ubisoft has released a 10MB video of Rainbow Six 4: Lockdown in action (mirrored on Eurofiles here) featuring members of the development team discussing the sense of immersion they were striving for and how they went about that.
Topics include the use of different view types for the two team members you play as - Ding Chavez and sniper Weber. Chavez sees the world through his goggles, which can be affected by the environment (most obviously through raindrops on the exterior). The idea is that the HUD is projected onto the inside of the goggles and electronics can be messed up by incoming fire and the like, while interestingly the goggles will actually crack up when you're really close to death. Weber meanwhile sees the world through a rectangular sniping view mode, with heads-up notification of enemy and ally locations through different-coloured arrows.
Development team members also discuss the sound design and how it was geared toward increasing tension and alerting you to enemy locations - through hearing footsteps on the floorboards above you and so on - and the video also notes the approach to character creation and particularly the need for distinctive voice actors; one of whom it turns out is none other than EG hero Wil Wheaton.
Rainbow Six 4: Lockdown represents a bit of a shift for the RS series, thrusting players into a "This time it's personal" style affair (in fact, worryingly, that's a line the team actually used in a previous trailer) as the team works to track down and recover a wayward comrade from nefarious terrorist-y types who have him under lock and key.
The full game should be released on PS2, Xbox and PC this 25th March.