Cooperative First Person Shooters
Or, ZDOOM Rules!
by Blake Linton Wilfong -- The Wondersmith!

I have a confession to make: I still play DOOM. Oh sure, I also like the magnificent graphics and smooth Internet play of newer First Person Shooters (FPSs) like Quake (in all its incarnations), Unreal, and Half-Life...but nothing beats teaming up with a buddy to explore new worlds and fight monsters in DOOM. It's friendlier than deathmatch, and no one needs to feel bad about losing since there are no losers (except the computer, who doesn't mind). My co-op modem DOOM buddy and I have been playing two evenings a week for about 5 years. Because people have created so many great levels for DOOM, we never have to play the same one twice.

But can't we explore new worlds together in the newer FPSs? Well, sort of. Half-Life doesn't inherently support co-op at all; and even when it's hacked to allow it, there tend to be problems due to its emphasis on storytelling and scripted actions. Quake and Unreal do have some degree of co-op support, but they're crippled compared to DOOM. Let's cover some features that greatly improve the co-op experience and see how these games measure up.


To enjoy playing a game with someone, it's absolutely critical that the players be able to communicate. Fortunately, most FPSs (including DOOM) are strong in this department; you can typically type out messages to send to everyone, or to specific teammates. Better still, you put on a headset, run Roger Wilco, and talk to your buddies. Though the DOS version of DOOM can't be used in conjunction with Roger Wilco, the brilliant Randy Heit has created a Windows32 port of the game, called ZDOOM, that uses DirectSound and TCP/IP networking and thus works with Roger Wilco. (You can get Roger Wilco at the Resounding website.) Plus, ZDOOM is playable over the Internet, and has many more great features for cooperative play--as we shall see.


ZDOOM's automap shows player locations,
keyed doors, and other helpful info.
Very often, while playing cooperatively, players get separated. Even if they try to stay together, they'll become separated when one is killed and respawns back at the start location. If they wish to join forces, or if someone finds a valuable item such as a weapon or key, or even if one becomes stuck and needs the other to come free him (or kill him!), they need a way to locate each other. DOOM solves this problem with its automap, which shows the location of all cooperative players. To find out where your buddy is, you switch to the automap and look for him. Alas, newer FPSs don't include automaps; they can't because there's no good way to map a truly three-dimensional environment with a two-dimensional map. DOOM clearly beats the newer games in this area; its "two-and-a-half-D" design is ideal for mapping since rooms cannot be situated above other rooms.

There's also a more subtle reason why the automap is important in cooperative play. Remember that I said we never play the same level twice? So, unlike deathmatch players who memorize every detail of the levels, or single players who keep trying the same level over and over until they master it, we cooperative guys are always tourists in the worlds we explore--and like tourists we need a map to help us remain oriented. We need to consult the map more often than other players because we're always in strange places we've never seen before. Among other things, it helps us see what areas remain unexplored. We can even give each other directions: "The blue key is in the room at the northwest corner of the map. To get there from where you are, head south, then turn west at the first intersection and follow the corridor all the way to the end." Try that in another FPS!

ZDOOM improves the automap further by marking keyed doors, teleporters, and level-ending linedefs with special colors. It also shows the total number of monsters and secrets on the level, and how many have been killed/found. All this information is helpful to us cooperative players who are playing maps for the first--and last--time.

"Spy" feature

The "Spy" feature in DOOM allows players to hit a key (usually F12) to switch to their co-op buddies' views, like seeing through their eyes. This is useful for all kinds of situations. For instance, when you're trying to help your friend find you or some useful item: "See that waterfall to the left? You can walk through it to get a BFG." Or say the red key is extremely difficult to the players agree that the guy who finally got it will be doorman, simply standing at the red door and letting the other player through whenever necessary. (It could be necessary many times if the level is tough and the other player is killed frequently.) It's nice if the doorman can watch what the other player is doing so he isn't bored silly. The "spy" feature is also convenient if you simply want to say, "Wow! Look at this cool architecture!"

ZDOOM gives players still more information: the other player's status bar. When you find a box of shells, medikit, etc. it's helpful to be able to quickly check your buddy's inventory or health to see whether he needs the powerup more than you do. Otherwise, you'll be constantly asking inane questions: "How many shells do you have? What's your health? Do you need this armor?"

The newer FPSs lack cooperative "spy" features--for no very good reason. Unlike the automap, there's no reason why they couldn't include it--but they don't. Shame on them!

Network cheats

In any FPS, it's easy for level designers to accidentally create situations that block cooperative play. For example: you walk into a room and see a nice yellow key, but the moment you pick it up, the door you entered through slams shut and another door opens to reveal a titanic monster. You die horribly. You respawn, grab up some weapons, and head back to try again for the yellow key...but you find that the door won't open again from the outside. Now you're sealed out from the yellow key and you can't finish the level. Another way this can happen is if you pick up a radiation suit, then get killed by a monster after (or while) you wade through some nukage. Now the radiation suit is gone, and you and your friend can't continue. Yet another example of poor co-op design: a collection of levels in which the later levels assume that players will still have the powerful weapons they picked up on earlier levels. This isn't necessarily true if the players have died and respawned after they obtained those weapons. My co-op DOOM buddy and I have had to inch our way through huge levels populated with horrendous monsters using only our pistols--a boring, painful experience. Or how about this: a crusher squishes you in a vital passageway, sealing it shut in the process.

ZDOOM has the solution to these problems: it allows network game players to cheat! Now you can walk through that closed door or sealed passageway, or give yourself another radiation suit or shotgun. Used sparingly, only when the level designer has made a mistake that inhibits cooperative play, cheating is a godsend. Everything is done right: network cheating can only be turned on or off by the server, and only through a command line switch at launch time (thus preventing the server player from turning on cheating only when he needs it). When someone cheats, ZDOOM displays a message for everyone else, telling which player is cheating and what cheat he is using.

Random Levels

This screenshot shows just a few
of SLIGE's many capabilities.
If you don't have time to look for and download levels to play every time, there's another way to constantly explore new worlds. A program called SLIGE will generate countless random DOOM levels for you--levels that work pretty well in cooperative mode without network cheats. It incorporates an amazing number of DOOM features: traps, crushers, windows, nukage, secrets, keyed doors, rising stairs, lifts, lighting effects, etc. and it combines these to create almost infinite variations in level designs. SLIGE even has a notion of themed areas built of textures that make sense together; one area will be built of wood, another of marble, yet another of steel and techno gadgetry. Those who are technically inclined can design their own new SLIGE themes using a configuration file. Though SLIGE isn't part of ZDOOM, the levels it creates work fine with ZDOOM. SLIGE is the work of programmer extraordinaire Dave Chess; he maintains a website for it here. There's simply nothing like it for other FPSs.

In conclusion, ZDOOM offers a host of cooperative play features that no other FPS can match. Though I'm probably going to enjoy playing Quake and Unreal with my new Voodoo3 card, I'll certainly still be running ZDOOM as well. Convinced? You can get ZDOOM for free here. You'll need DOOM, DOOM II, or Final DOOM to use it.

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