Okay.  Beat the game last night on medium and immediately loaded up a new game on Impossible.  Not too tough yet, but I'm only on Chapter 3.
I do want to point out how lame I thought it was that all the stuff you unlocked after beating the game is only available if you keep playing on that same difficulty, but it makes sense.

Anyway, how many of you guys are playing on Impossible now?  Are you farther than chapter 3 and do you really think it is that much harder?

I only ask because so far, i don't see that huge of a difference.

I played about 10 minutes of it, already seems hard. :P

Gonna beat the game with all my stuff first so I can snag some of the easier achievements, and upgrade all my stuff.

"I played about 10 minutes of it, already seems hard. :P

Gonna beat the game with all my stuff first so I can snag some of the easier achievements, and upgrade all my stuff."

I am on chapter 8 or 9 right now.  My advice, only use the cutter, don't even buy anything else.  Just ammo and health packs, try to keep at least 75 rounds of ammo on you at all times.  On the Leviathan fight you will need about 100-150 though.  I am at the Valor right now, I have the level 3 suit still.  The only real difference is the enemies insta-kill you faster and take off massive chunks of health with every attack. 

This is good to hear actually.  I'm hoping to get my first platinum with this game but I was worried I may not be able to get through Impossible.  Sounds like it's do-able just may take some time.  :D

I've just started on the sixth chapter and I'm also trying to get all the remaining achievements, such as the "kill 30 enemies with the whatever" ones, the secret ones and ofc the one for  beating it. Also, I never got that shooting range score the first time through. Anyway, it's significantly harder, but nowhere near "impossible". It's actually quite managable.

If you are looking for a good achievement guide, Vinchenzo has one up here on GB somewhere.

I just got Platinum today (all the trophies for all you non-ps3 users). I did my final run, "One Gun/Epic Tier 3" which means, I went on Impossible mode and only used the plasma cutter. Personally, I thought the game was rather OK, not too hard, but not easy, like someone said manageable, that was up until Chapter 9 and beyond. That was when the shit started hitting the fan.

At first I thought that you only get ammo that corresponds to what you have in your inventory, but that isnt case, as you get all types of ammo no matter what. Specially on that ship that crashed, theres only one Store, and thats after that massive room brall which almost made me want to chuck my remote control at the screen.

I didn't mind that I couldnt carry my weapons over, maybe because I really didn't need them, except for one, but shit, all this useless ammo, and the fact that it would out number the plasma cutter ammo I was getting in drop ratios was driving me insane.

Like I said before, I thought it was easy, until chapter 9. Resident Evil 4 all over again :|

I'm on Chapter 7 and the only things that really give me problems are the guys with exploding arm tumors. Those will kill you every time if you let them sneak up on you.