I beat it the first time on friday night, and had played it for probably 20 hours total...just played for about 5 hours a day total between work and school...
The longest part was the end boss...I don't want to give that away, but I spent almost all of friday evening trying to beat it...
I then started it on the medium difficulty...and it goes a whole lot faster once you know all the secrets...I remembered most of the little stuff, and the ways to beat all the bosses...so I finished it again yesterday...Trying to go through the ultra-violence one tonight, and then on to nightmare...I have heard that nightmare is just insane...and I can imagine...after playing Q3 for 5 years, I still could only beat like one person on nightmare...
Overall I like Doom 3...But I remember liking Doom 2 more...I was mentioning earlier, the staged crap is just annoying...and gets old after the first time it happens...This game looks great, but it attempts to scare you too much...and if you are expecting attempts to scare you, it doesn't really do anything...Doom 2 was much more open, and at the time looked really good...After the visual shock wears off, there isn't a whole lot more to flip out about...
yeah turfburn, the heat haze thing is insane...You probably don't have a rocket launcher yet...but you do have a 9.X video card right? You should see hazing and blurring over anything hot in the game...On my A51, even the steam from broken pipes has all kinds of hazing all over it, and those crazy burning zombies that lumber after you while on fire...Also fireballs from imps, you can see the hazing when they hit a wall or something...
Its tough to see sometimes, because it is a transparent affect...there is no change in lighting associated with it, it simply warps what is all ready there...So look for it in well lit areas...if you see a barrel in open light, pay close attention because you will probably notice it...Towards the end you will definately notice it though, because you are arond lava all the time...and above the lava you can tell it looks similar to real heat...