I just finished re-playing Doom and Doom 2, ala GZDoom. The original games are available on Steam, which also means you can still legally purchase the required WAD files for mods such as GZDoom, ZDoom, Chocolate Doom, and Brutal Doom.
Graphics and Art Style
When originally released Doom’s graphics were quite pixelated, primarily due to the low-resolution screens available at the time (but also taking into consideration it wasn’t until GLQuake that hardware rendering would be used). However using one of the mentioned mods above for higher resolutions and very smooth graphics and movement.
As for the look, Doom’s artwork perfectly matched its motif of hell meets technology. The monsters and environments are dripping (sometimes literally) with flavor, slime and blood. In particular the Cyberdemon is exactly the creature of hell I would imagine as the worst fate you can imagine meeting.
This opponent is pretty simple; he shoots with a pistol and doesn’t deal very much damage.
Former Human Sergeant
These guys are not to be under-estimated. Far away they may sting a bit like the Former Human, but up close they will rip through any armor you have and put you on the ground before you know it.
Heavy Weapon Dude (Doom II)
Dudes with chainguns. Unlike you they never run out of ammo.
Pretty slow and stupid, their fireballs are easy to dodge.
Demon / Spectre
These guys don’t deal a ton of damage, but they also can take a lot themselves before dying. Also, they are happy to surround and pin you down, so keep moving and don’t get cornered.
These flying orbs are basically like Imps, not too deadly and easy to dodge.
These flying skulls are annoying, and they tend to fly in packs. If they see you they’ll fly right at you quickly, so don’t ignore them.
Pain Elemental (Doom II)
These flying Lost Soul belchers are annoying. If you don’t kill them you’ll be surrounded by Lost Souls, and then you kill them a few more will pop out anyways.
Hell Knight (Doom II)
The weaker brother of the Baron of Hell, they can still deal some decent damage and sound scary as hell.
Baron of Hell
The original humanoid of hell, these guys can take quite a beating before dying.
Arachnotron (Doom II)
Infinite ammo like the Heavy Weapon Dude, but fairly weak in return, so be sure to put them down quickly.
Revenant (Doom II)
Fast and deadly, Revenant shoot homing missiles that pack quite a wallop.
Mancubus (Doom II)
These tubs of lard deal decent damage, but can take awhile to kill.
Arch-vile (Doom II)
If you see one of these in a group you need to kill it first, otherwise it’ll keep resurrecting baddies. When you see the flames around you try to block his view, otherwise you’re gonna get hit badly.
The original bad guy, they make Barons look like pansies. Their infinite missiles will mow you down before you can run away, and they take forever to poke a hole even with the deadliest weapon at your disposal.
Weaker than the Cyberdemon, but you can’t dodge the infinite bullets it spews out.
Somehow deal more damage than the pistol, combine with the Berserk power-up for some real carnage.
Fun to use and helps conserve ammo.
The default weapon is pathetically weak, find an upgrade ASAP.
The workhorse for clearing out rooms, and also has some decent range.
Super Shotgun (Doom II)
Absolutely deadly up-close, but slow to reload and chews through ammo.
Great for distance kills, and doesn’t go through ammo as fast as you’d think.
Packs a wallop and easy to home in even while running around. Just don’t let it hit nearby or you’ll get splattered too.
Extremely high rate of fire, fun to melt down anything getting in the way.
Hits very hard and also helps clear out nearby annoyances, but slow to fire and consumes ammo like a cow on a dirty bulk.
Sound Effects and Music
The sound effects in Doom and Doom 2 are very distinct and punchy. The enemies have a variety of noises covering when they see or hear you, as they’re taking damage, and finally when they’re killed. The weapon sounds are quite satisfying, especially the shotgun.
All the music in Doom and Doom 2 was composed by Bobby Prince. There’s a lot of variety here, from quiet brooding synths to up-beat guitars and drums.
There’s a lot of levels between Doom and Doom II, with those of the first game tied into each other a little better. Doom II has some strange outdoors/town maps that just don’t really fit the motif. I really like the latter levels of Doom, as those have a more sinister and hellish feel and look. My favorite map is the final map of Episode 1 (Knee-Deep in the Dead) featuring 2 Barons of Hell. I really like the simple layout and look of this map. I don’t know what it is but the star-shape is quite creepy, and the mountainous background hints at far more than is ever seen in the actual game.