DOOM may be old, but its F12 "spy" feature and automap are ideal for co-op play. DOOM II Maps Tested under DOOM II, BOOM, or ZDOOM
Pass
Add-on	Size	Levels	Date added	Comments
Co-Op Quickies	0.3M	11	12/8/2000	Made for co-op! 11 small but intense maps created by fellow co-op player Dan L'Ecuyer. Recommended.
City of Doom	3.1M	11	12/8/2000	Spectacular! Great level design, very tough combat & puzzles, city streets & buildings theme. (Last map may have a co-op hostile trap, but didn't cause us trouble.) A must-have!
The Mission	0.3M	6	11/15/2000	Follereau Dominique's classic map set, updated for co-op play by the Co-Op Certification Laboratory. Good stuff!
The Darkening, Episode 2	4.6M	12	11/2/2000	The current version 1.1 corrects co-op problems we reported to the authors. Bravo! Excellent levels; don't miss this.
Perdition's Gate	N/A	32	11/2/2000	Commercial megawad by WizardWorks (not to be confused with the freeware 6-level wad reviewed below). One spot in one of the early maps suggested a potential co-op hitch, but it didn't happen to cause us any difficulty.
Hello!	1.2M	14	8/11/2000	Made for co-op! Some levels are a bit simple, but all are good tough fun.
Atlantis	0.1M	1	8/11/2000	Good solid action and puzzle-solving.
Lynx	0.1M	1	5/13/2000	Silly map layout concept, but tough and fun anyway.
Sudden Death	0.8M	1	5/13/2000	Another grand, violent King REoL wad. Small gripe: keyed doors should stay open.
All Hell Is Breaking Loose	2.5M	5	4/12/2000	Amusing Partial Conversion crashed ZDOOM a lot, but no co-op problems.
DOOM 2200 Episode 1	1.6M	6	1/23/2000	VERY tough levels, superb co-op play.
Earth	1.3M	10	1/9/2000	Magnificent! Admire it with your friends.
Bitchin' 97	0.9M	10	1/9/2000	Made for co-op! Hellacious combat.
Dimensions Of Time	1M	32	1/9/2000	A simple but entertaining megawad.
Realm Of Shades	1.5M	7	1/9/2000	Fantastic! Big, interesting levels, huge battles.
Perdition's Gate	0.7M	6	1/5/2000	Good mix of action and puzzles.
KZDOOM1	0.3M	1	1/5/2000	Great level by Kurt Kesler. Showcases ZDoom features.
Lovinger Outpost	0.9M	8	1/5/2000	Perfect co-op levels. Get it.
Enigma	1.3M	9	1/5/2000	Spectacular levels by Jim Flynn.
SLIGE	0.1M	zillions	1/5/2000	Random wad generator produces surprisingly good co-op-friendly levels.
Fail
Add-on	Size	Levels	Date added	Comments
10 Sectors Megawads	varies	32	12/8/2000	Missing co-op starts & many other problems.
Tun-Run	0.3M	1	11/15/2000	Doors sealed shut near start, yellow door didn't work.
TeamTNT's Doom 2000	???	32	11/2/2000	Not even out yet, but we were disappointed to learn from TeamTNT that this won't support co-op play.
Hell to Pay DSV World KZDOOM3 KBOOM12	Varies	Varies	11/2/2000	Due to the technical problems (e.g., lightning-zapped computer) we encountered throughout testing, we don't have records of the exact problems we encountered with these wads, but they all failed for various reasons.
Hellbolt	0.1M	1	8/11/2000	Door sealed shut near start.
"Last Day on Earth" (LASTEP1)	1.0M	11	8/11/2000	Once-only door switch, lots of traps seal up.
Helldoom	0.4M	8	8/11/2000	Unable to exit map 4.
Biowar	1.9M	19	4/12/2000	The usual problems. (Sigh...) Don't bother.
Hell Revealed 2 Part 1	1.6M	17	2/26/2000	Doors won't re-open, bars seal areas off, etc.
Herian 2	7.6M	32	2/26/2000	Door that don't reopen, one-time tporter, no "Things", etc.
STRAIN	5M	32	1/9/2000	Co-op-hostile traps block keys, etc.
The Talosian Incident	1.4M	20	1/9/2000	No co-op starts on map 2.
Enter the Night	0.3M	4	1/9/2000	No "Things" in co-op mode, plus problems with traps.
Realms Of Devastated Eternity (RODE)	0.9M	6	1/9/2000	Missing co-op starts on 2 maps + other problems.
Master Levels for DOOM II	3.3M	20	1/5/2000	Commercial add-on from id. Sealed out of tower, etc.
Batman DOOM	5.6M	32	1/5/2000	No "Things" in co-op mode.
Pixel Rex wads	varies	1 each	1/5/2000	Includes Simply Evil, Jagged Edges, etc. All lack co-op starts or have no "Things".
Operation: Arctic Wolf	5.6M	??	1/5/2000	Doors wouldn't reopen, one-time teleporter.
KZDOOM2	0.3M	1	1/5/2000	Walls move for 3-D effect, blocks co-op players.
Older Kesler wads	varies	1 each	1/5/2000	KBASE, KMETL, KHILL, KBRICK, KBOOM all lack co-op starts.