Doom I: The nightmare begins...
In Doom, you play a Marine who has to escape from a military base on Mars that has been overrun by demons and various other nasties from hell. With an assortment of weapons at your disposal, you must venture into the maze of corridors and rooms, trying to find a way out, whilst all the time fighting the hellspawn that seek to destroy you. But things get worse! In order to succeed you have to follow the monsters into hell itself, there to fight even more vicious creatures and, eventually, to track down and destroy the the evil mastermind behind the invasion. Can you do it? Do you have the guts?? Grab that shotgun, check your ammo and get to it!
Doom II: Just when you thought it was safe to put down your shotgun...
So you've beaten the bad guys, the fighting and mayhem is over and you're on your way home. All seems well, and you've come out of it a hardened tough marine. Time to relax and get some R&R.
But wait! What's this?? You get out of the drop-pod and see flames! The city is on fire! It seems some surviving hellscum have followed you back and are now on Earth! Cities across the land blaze, chaos reigns and the populations of the world are either dead or turned to cannibalistic zombies. You're not out of it yet! Raising your shotgun, you march forward - time to face the marauding denizens of hell once more...
(I'll add some info about Ultimate Doom when I get a chance to play it. :D)
There are rooms, corridors, slime and acid pits, walkways, etc. Many different textures are used, with subtle lighting and excellent sound effects that add to the atmosphere. There are toxic waste barrels (shoot them and they explode; useful for splatting a monster at a distance), moving doors, rising pillars and all manner of other items and power ups that can be collected along your way.
It's not all shoot, shoot, shoot...
Doom does have a degree of puzzle-solving to make things more interesting. There are hidden rooms, secret doors, traps, etc. Switches activate rising pillars, or open doors elsewhere. Some doors need special colour-coded keys to open; obtaining these often means entering dangerous areas and finding the various secrets that will lead you to your goal.
Sometimes the next step you must take may not be obvious - have you missed a secret passage? Is there a switch you didn't press? Dark tunnels may lurk in unexpected places, but run down them quickly as they may be full of acid slime (perhaps there's something that could protect you from the slime? A radiation suit may be hidden somewhere - go back and check).
Sometimes switches and levers have to be pressed in a certain order to gain access to hidden areas, but watch out! Walls may open, releasing creatures just waiting to turn you into muncemeat.
Things are not always what they seem though... is there a secret panel you missed in your haste to escape? Weapons and ammo may hide behind that wall... check again. Look for signs and clues: flickering lights, strangely coloured walls, or listen for sounds that signal a secret door opening somewhere (Doom is best played with a good soundcard).
A frightening array of creatures await you in the world of Doom. Many are much harder to kill than others - some of them are even your former buddies turned into maniac zombies and raving lunatics!
You've no choice though. It's either you or them.
But the monsters aren't as smart as you are. They'll even fight each other! And if you're careful in your movements, you can make them fight one another (in the sequence shown on the left, I made an imp shoot at a seargent; the seargent fought back, killing the imp, but a second imp then splatted the seargent!).
Sometimes, when you're low on ammo, making the bad guys fight each other might be the only way to survive...
When monsters die, grab their dropped weapons and move on. Move quickly though! Tarry too long and others will find you, intent as ever on rearranging your face if you give them half a chance.
[here is the montage above as three separate images: Image 1, Image 2, Image 3]
In general, the tougher a monster is, the less it can harm its own kind. You will have to learn their ways if you're to survive.
You can save your position, record your playing sessions and even create your own add-on levels (there are hundreds of such extra levels now. Read the Doom newsgroups or examine some of the help files available from the DHS to find out more).
Doom tournaments exist in many parts of the world now. Are you up to a challenge? If so, check out your local Cybercafe or ask on the Doom Internet newsgroups - there may be a Doom competition in your area (if there isn't, why don't you organise one? :).
Doom is a fairly extensive phenomenon; there is a lot that can be done, from just playing the game to taking part in Doom tournaments and creating brand new levels for yourself and other people to play (many add-on levels that have been made are of exceptional quality), so don't feel too daunted by the shear volume of information that's available. Take what you need to begin with and investigate the rest later.
If you have any questions, feel free to email me.