This type of idea has been tried before, the Aliens vs Predator title a few years ago had the same idea but feel down as the Marines overpowered the Alien. The test for this game is how well would the One control and how balanced is the game.
Firstly we were playing on pc's from Chillblast with 360 controllers so I was straight at home. Unfortunately my audio was down so I had to play deaf, it made the experience a lot harder as I was getting shot from unknown angles but handily the bullet trails are present.
So I played as the monster in a mode called hunt, the principle of which is that the monster must either kill the hunters or destroy a specific target. Obviously for the hunters the roles are reversed.
As you start the game the Monster spawns thirty seconds ahead of the hunters, then as Jon likes to say its time to get the he'll out of dodge as you start as a weakened character. In this initial time you can level up by killing wildlife and chowing down on their carcasses. Once you have eaten a set amount you can then Evolve and rank up some of your attacks. Obviously while your eating or evolving you are vulnerable to attack but you have a handy smell feature which you use to find incoming threats. This mechanic works like a wave and works really well to give you the help you need in finding prey.
The great thing is the whole experience felt balanced the monster gets progressively more powerful and if the hunters decide to hunt you while your small then you will be in trouble but thanks to the dual objectives there is also the desire to protect the objective. The team playing me gave me time to rank up and I managed to everyone to level three and then went on the hunt from them. My first attack went a little wrong but I was able to skip out regroup and regenrate. Then with time ticking down I decide to go for all or nothing and then the Monster mechanics really came onto their own.