Ive just started to play the game on impossible diffucilty. And have to say it seems 1000 times more tense, because every bit of ammo counts, and you have to make sure your Node things are used correctly when upgrading. and you also seem to watch your back more because the neco things move faster and even dodge your line of fire.
Anyhow i love the game it is defo one of my favorite games in a long time. The only thing i would say the game could benefit from and future games like dead space would? is having some sort of enemy A.I director like Left4Dead has, were the enemies always spawn in different areas when replaying the game. Just like most type of horror games of this nature, you always know were the bad guys are gunna be when replaying the game for a 2nd or 3rd time... But other then that, what a great game.
