Most of this stuff is taken from the DOM e1m3 text file.
Doomed Once More background story:
Doomed Once More follows pretty much the same plot as the original Ultimate Doom. You know, UAC, gateways getting fucked up, your team goes in, you're left to "secure the perimeter" with only a pistol, etc. You will start episode one in a little guard bunker outside the landing zone. After you clear out the LZ and the storage facility (E1M2), you will arrive at the Phobos Living Quarters, which is E1M3.
Episode One: Fear
Map Title: No Quarter
Music: "The Wind" (Mark Klem)
Inspiration: Originally started out as a level for the ill-fated Doom Revisited project, so I decided to take it and center my own project around it. The goal was to make a level (and hopefully an entire megawad) as realistically as I could.
Description: Takes place in the living quarters on Phobos. Your primary goal here is to activate the monorail and use it to progress further into the Phobos facility. The monorail isn't active because several portions of the monorail tunnels have collapsed, causing the safety overrides to set in and stop all monorail service.
You start out in a little service elevator. From there, you'll head up to the mess hall, and then the recreational facility. Inside the rec facility is the blue key, which will give you access to the troop quarters. Located in the troop quarters is the red key, which in turn allows to you enter the officers' quarters. Once there, you'll have to activate the monorail from within the monorail control center, then head up to the monorail station to exit.
There are eleven secrets in this level, including the yellow key, which isn't necessary towards completing the level, but will give you access to lots of neat things, and the secret exit, which will bring you to E1M9, which is a stockade/armory.
Additional Notes: In terms of difficulty, this level isn't overly hard. Don't be overwhelmed by the large monster count, since they are all rather weak (the toughest is a demon). There are, however, several somewhat tough battles, but this level should be a mediocre challenge for the average Doomer.
As for health and ammo, there isn't a whole lot of spare health floating around, but there is certainly enough to go around. There are also two soul spheres, if you can find them.
I didn't put much ammo in this level on purpose, for two reasons. One is that in the final version, you will be coming from the first to levels in episode one, and you should have some ammo left over from those. The other reason is that due to the huge amount of enemies that drop ammo (former humans and shotgun guys), it will be hard to take a step without picking something up, so ammo really shouldn't be a problem.
If you can't find some of the secrets, don't get angry. There are eleven, after all, and many of them are quite hard. Remember to "interact" with objects such as computers if you get stuck. There isn't a single inaccessible area in this game, except for the deathmatch area, so don't worry. Just keep looking, and you'll eventually find it.
Map Title: Observing Death
Music: "TechnoDoom" (Mark Klem)
Inspiration: I recently learned how to use the "silent teleport" trick using line type 244, and I wanted to make a level showcasing that feature.
Description: Basically, after the monorail you escaped in from E1M3/M9 crashes, you're stuck at the observation/communications towers on Phobos. Fight your way into the sewers. More info later.
Map Title: Gateway
Music: "Tempter" (Mark Klem)
Inspiration: Basically, just the original E1M8. I wanted the dual-baron, tag 666 battle with a realistic twist, plus a giant room with the gateway. All of that was accomplished.
Description: Kill the barons and step onto the gateway to end the episode. Hurrah.
Map Title: Stash
Music: "Rumble in the Brain" (Mark Klem)
Inspiration: None, really, just a small, sweet, quick secret level.
Description: This is the secret level, an armory with weapon and ammo storage. Have fun collecting the ammo, as you'll need it for E1M4, then head back into the room you started in to get back up to the rail station at the end of E1M3.