Some musings on the role of the suspicion meter in the 'Hitman' franchise:
Also, there are good examples at GameVideos.com and at Gamespot:
The 'Hitman Blood Money' video review by IGN's Douglas C. Perry is about 5 minutes long and pretty thorough. About 60% of the way through he talks briefly about the 'suspicion meter' but you can see it during all the gameplay clips--it's on the lower left, beside the health bar, and its function is pretty obvious. However, manipulating it during gameplay can become subtle via familiarity with the game's engine--for example, you can learn how to push it as far as possible without allowing it to spike into the red by running, then walking, then running again...or walking down a forbidden passage, and turning your face away from the guard as he passes by, (even though in real life, that might appear more suspicious than just walking by). Most importantly, the game employs disguises, whereby you don the outfits of people you've killed or rendered unconscious, (and whose bodies you've hopefully stashed away, to avoid discovery). If you have the right get-up for the occasion, your presence will not warrant undue attention. Taking the uniform of a cop or hired goon is often the most useful. During gameplay, you are constantly referencing the gauge to get a sense of how the NPCs/narrative design is reacting to your decisions. And naturally, you will find gameplay points where you make a wrong move, the bad guys go bonkers, and you just immediately quit the game and load your last save--because that play-through is a bust. 'Hitman' has a generous save system: on normal difficulty you can save up to seven times within a single level, (which you might do after each story progression), but unlike in past Hitmans, all inter-level saves are lost if you turn off the console before completing the level. The levels are so beautiful, and can be completed in so many ways, it is not a drag to replay them, in my opinion.
When I first played 'Hitman Contracts' I was very impressed with the 'suspicion meter.' It gives the world a tangibility and a suspense--and it gives personality to the NPCs. They are watching you and responding to you. However, the flip-side, as I said, is that you can begin to manipulate their reactions via mechanics of gameplay.