"Daniel Gimmer headed up the Knee Deep in ZDoom project, which finished back up in 2007."
It was an attempt to render the original Doom shareware episode with the advanced features of ZDoom. Since then, The Shores of ZDoom has been a work in progress, and while Tormentor was on the title card for awhile, the project has since evolved beyond him. The Refinery, a single map he released in 2012, was his major contribution to the project, now released as a standalone while the Shores team no doubt busies themselves with their own take on Doom's E2M3. Err, yeah - in case you hadn't figured it out, this level is Gimmer's take on "Refinery" ZDoom-ified.
Actually, to be fair, it's not so much "Refinery" ZDoomified. Gimmer attempts to channel a survival horror aspect a la Doom 3 with tight ammo and health, slow acquisition of armaments, and enemies selected to deliberately slow the pace of the game down to a crawl. Other features like ambient noises and scripted sound effects help to drive the point home. To further the comparison, you don't even start with a pistol; it's the centerpiece of the first major encounter. There are a few entrenched monsters you'll want to steer clear of starting out and a couple you'll have to dodge through on your way to your first weapon. Well, you could probably punch the flies out, but you're better off going back with a gun, as silly as both options sound.
The main gameplay issue you'll encounter is Gimmer's fetishistic use of super-powered zombies, which are incredibly dangerous starting out, compounding the early lack of health and armaments and no difficulty levels. There are rocket zombies, autoshotgun guys, quadshotgun guys, SMG zombies, and the occasional headscratchers like railguns and repeaters. The Refinery is a really bad place to be unless you're up for constant saving. Once you get some better weapons and sort your health woes out you'll be sitting pretty until your fight with two vores. I could barely tell what was trying to kill me at first, but once you get hit by the first super-fast pod you'll figure it out.
Those are really the only threatening things about the level, though the zombies are omnipresent. I like most of the rest of the monsters used. Those hanging corpses and swarms of flies don't fit very well but the wraiths and imp / hell knight stand-ins are fine by me. The pustules and tentacles were barely even a factor. I don't think I could pick a standout encounter; I spent more time peeking around corners and chaingun sniping than really being engaged in a shootout. I suppose the one at the west end of the L-shaped tunnel with the red key door comes pretty close. The Refinery is more about whoever shoots first, though, with its nasty zombie population. I have way more fun killing all the projectile-throwing monsters.
Gimmer has certainly "prettied" up the place. Not having E2M3 imprinted on my mind, only a few sections stood out to me as clearly belonging to the original, but enhanced. It's just too faithful to it in one big way - excepting some of the earthy tunnels, most of the action takes place on the same plane. Height variety is the spice of Doom life so leaving things as they stand is kind of, well, lame. There are still some neat bits, like falling through the ground into a lower area and then climbing your way to the top, but you'll generally be shooting at monsters (zombies) at or around your height.
Now, if you manage to suffer through the initial run, Torm throws you through a second gauntlet, crammed with even more monsters. It's got kind of a jam-packed OG Doom feel, except for, you know, sonic railgun snipers and auto shotgun guys. The upshot is you get all of the weapons much sooner and the progression is "remixed", sending you through areas in a different order and making more use of the Doom bestiary, with imps, lost souls, cacodemons, spectres and a few different scripted sequences, including a fight between some ZSec troopers and a horde of imps. Gimmer managed to find the most annoying placement for vores, though, down to the surprise finale where you'll love your plasma rifle.
The two different playthroughs offer two different playstyles a chance to shine. The first is more like survival horror, with tighter restrictions on when weapons and ammo show up in addition to health, while the second is more flush with goodies. Both are let down by omnipotent zombies and a layout that just isn't that dynamic. If you're into hiding around corners while you contemplate your next move, you'll probably have a fun time enduring the crawling chaos. For your average player, I can't recommend it except for maybe some sightseeing given its uncompromising attitude with regards to difficulty levels, but you're more than welcome to try!