Also, all the interaction you make with the world is permanent. This means, guards who spot you won't forget about you as they do in other games. If they spot you somewhere, and you are unable to kill off the guards who did, they'll alert the rest of the complex that there's an intruder, and try to flush you out until they're sure you're dead. They'll remember where they last saw you, and make assumptions about where you'll turn up next.
The interesting part here is, the first guard you kill, will drop a com-radio. You'll hear all the chatter between guards about what they think you're up to. This will also be shown on the map, with indicators pointing where you were last seen, and if you have those parts of the map, indicators where they expect you to currently be.
The guards expectancy levels are also dynamic. If they spot you in the ventilation system, they'll know to expect you from vents.
Imagine Riddick: Escape from Butcher Bay, except more free.
