The main problem in this game is that you do not find enough clues to perform some tasks. However I love it.
It takes some time to get use to its mechanics and when you think you are the king of the town, suddenly an extra load of difficulty appears in form of a stronger shibito (The zombies of this game) or a stupid character you have to save from them pawns.
I think the game developers have commited some mistakes. Ten caracters stories interact, so what you do with one caracter during a mission can unlock posibilities for another (F. Ex. You get some candles during a damn hard mission, therefore in the next mission you can use them. Sometimes you get something with one caracter to give it to another so this one can use it in another mission) And here lies the first mistake (I know you all siren lovers are gonna say because I am one, but I LOVE good stories, particularly the horror ones and some aspects of this game detracts tons of people from witnessing a very nice horror story, what is, in my opinion, a real pity) You do not know in the first place which is the usefull thing that unlocks another level or where it lies. You must explore by yourself what is not imposible, but quite hard due to some sniper (Yes you have read this well and I am not drunk ... well maybe not that drunk... just kidding, Gamespot recommends you should do some exercise and deliver a healthy lifestyle) And about this searching, if finding things was not hard enough, there are some levels that are splited in two. If you die in the second part you can restart from that point what is very useful most of time if it wasn't because you LOOSE every single object you have found in the first half of the level. Actually on those levels you have to start again all over from the beginning. You have to save sightjacks AGAIN in the face buttons (What is a really tedious thing to do) and be perfect.
However even with this mistakes the plot is terrific and you really spend a great time being PERFECT. I love this game.