Finally, after months of effort (well, there were months of gaps between levels), I finished the single player levels of DooM-3. Can’t deny that I get a sense of acheivement from this thing. Particularly when most of my friends say that they would not care to go beyond 10% of the levels without using cheats. I used no cheats, but there were a few occations where I used walkthroughs. Almost everytime I would finish the level and come and check what Mike at Visual Walkthroughs has to tell about the level. Occasions where I actually got unstuck with help from the site are :

1. Making sure that ‘jumping across’ is the way out from this place one of the service bridge in Alpha labs 4:29
2. Got confused and irritated by Enpro plant exit. I could not find airlock (was scared to go into the dark) to exit.
3. I did not know that I had the code to the BFG chamber, till I saw it in the walkthrough.
4. Missed the PDA mentioned here in Monorail and went in circles without a way to get out past this turret.
5. Killing guardian: Was bit troubled about too much time I spent to figure out how to kill it.
6. And… the easter eggs (Turkey puncher, message on hitting Classic Doom cheats and the id software PDA).

Finished all the remaining levels without help (including killing Sabaoth, twin Vagaries, and even the Cyberdaemon).