The following is the text (only slightly edited) of a post of mine to the DOOM Help newsgroup. Added comments are in italics.
To: rec.games.computer.doom.help@dispatch.demon.co.uk[dispatch.demon.co.uk was a mail-to-news gateway, now closed]
Subject: >>> SPOILER <<< TNT MAP30 -- the safe path through Copies to: mapleson@deletethisbit.gamers.org[Ian Mapleson, who runs the DOOM Help Service]
Send reply to: robert.bak@deletethisbit.bigfoot.com[that's me, of course — who else?]
Date sent: Fri, 20 Sep 1996 16:55:42Q. I’ve fought/warped/cheated my way to level 30 (Last Call) of TNT.WAD (Final DooM aka DooM95), and can’t get across the lake. Whenever I jump to one of the blocks, there’s a teleport flash and I end up dead in a dark place. This happens even in God Mode! What the hell (excuse the pun) is going on? Is it possible to get across?
A. (by ROBERT.BAK -- robert.bak@deletethisbit.bigfoot.com)
Of course it’s possible, otherwise you couldn’t progress!, but this is probably one of the most fiendish (excuse the pun again) traps ever set in any DooM WADfile! What the TNT crew have done is to set up a second Player 1 start in a dark sector isolated from the rest of the level, and most of those innocent-looking blocks are surrounded with linedefs that teleport you onto this second copy of yourself. Result: cross one of those lines and you telefrag yourself.
As you may already have learned the hard way, God Mode does not protect against a telefrag, nor a spawnfrag.
The following map shows the path (in Navigator, right-click on it to save it):
Click here to download a demo of me crossing the lake (after disposing of the nasties in the way, of course — not very well, I’m afraid). A (suspected) bug in my copy of DOOM95.EXE prevents it recording demos, although it will play them; to make this one, I had to copy DEFAULT.CFG, DOOM2.EXE and TNT.WAD (as DOOM2.WAD, of course) into a temporary directory for this purpose.
Copyright © 1997 Robert J. Baker. All rights reserved worldwide.