Hangar
The episode starts out with you gunning down zombies and imps in the hangar, and quickly you recover the shotgun. You have limited ammo with the shotgun, so you'll be using the pistol a lot and switching to the shotgun for the tougher monsters. Health is a bit overabundant in the beginning, at the beginning I got several medikits thrown in my face when I wasn't injured at all. Balance was better near the end. There were plenty of monsters though, and I had a blast! Personally I don't like the pistol that much as it slows the gameplay down when you slowly shoot little chips off the monsters, but it works, and is a matter of preference. It was still fun, and I managed to stay alive all the way through. I was, however, unable to find any secrets.
Nuclear Plant
Immediately as you enter the nuclear plant, a sense of nostalgia hits you as it starts out exactly as the original. I think this is one of the maps that preserved the most of the original map it was based on, and was also a blast. Once more I could have used some more powerful weaponry, but that was my own fault as I managed to miss the chaingun near the start of the level, and had to use the pistol extensively. Still, the difficulty wasn't high and I managed to get by easily. Still no deaths, and found several secrets. A critique is the amount of armors... I don't need several additional green armors when my armor is already over 100.
Toxin Refinery
This was one of my favourite levels of KDiZD. There are many familiar areas from the original, and they have been touched up so well that I almost dropped my jaw when I entered the area with the nukage donut. I was slightly disappointed when I grabbed the keycard in the room behind it and the room didn't go dark. But when I got back to the door it shut in front of me, and I thought "Oh yes!" and the room went dark and the monsters came! It's little genius twists like that you will see all through the episode, but this was easily my favourite. Another great map! Having both the chaingun and shotgun, this was a walk in the park. Again too many armors lying around.
Command Control
This map started out great but as I missed a switch at some point it gave me headaches as I spent close to 45 minutes just running around randomly trying to find it. I managed to find it at the end in a dark corner. I wish this would have been more clearly marked, and perhaps put in the middle of the wall so you see it immediately as you peek into the area. Can't remember the area exactly anymore, so I can't specify more clearly where it is right now. Another easy map for me, and still not dead. I think it was in this map where I started with close to 200 health from a soulsphere from the previous map. I didn't get to pick up a single health pack in this map as I didn't drop below 100.
Phobos Lab
Pure awesome, though perhaps a bit too much ammo lying around. I'm starting to pick weapons based on which ones have full or nearly-full ammo, rather than based on which ones are low on ammo. Greatly succeeds in capturing the feel of the original. My only complaint is the big use of the black imp variant that shoots huge balls, as I feel these are over the top and not needed. They aren't difficult, but merely look silly with that huge energy ball (I think it sometimes homes a little bit as well?). My favourite part of this map was when I revisited the beginning and found two satyrs coming out of a hellish passage emitting an eerie warm glow. I loved how the passage was made. It was a bit silly that Tormenter's head was in it, but I guess that's more fun for the team than for the player

At least he was kind to drop me a soulphere when I blew him up with my double-barreled shotgun (which, incidentally, rocks). Was easy on HMP, and I think I managed to find quite a lot of secrets in this one.
Central Processing
Had a lot of fun in this map, despite the overabundance of ammo. At this point I'm having serious trouble getting rid of the ammo. I like how some of the levels put you outside the actual facility that you're entering, and this map does that as well. It had a nice mix of inside and outside areas and the combat flows well. I managed to kill myself in this map when I tried out the grenade launcher and it bounced in a really odd way and killed me outright despite the fact that both my health and armor were well over 100. But this way I discovered that the grenade launcher was actually a great deal more powerful than I initially thought, and I started using it much more (and with more care). Apart from that, no problem getting through the level.
Computer Station
Awesome! Some of the areas in this map looked a bit iffy texture-wise, but other areas look really awesome as things start to become more hellish. I'm a big fan of the SNAKE textures used cleverly as well (another great example of this is the dark passage near the start of the first level). I thoroughly enjoyed this map. Pickup balance was as I recall also much better in this map than the previous ones. Nevertheless, the demons were no match for me and I had a blast making sure they knew!
Phobos Anomaly
This map starts out incredibly nice, the passage where the screen grows red and the area is suddenly "hellified" and cacodemons come at you from the windows was one of the coolest tricks I've seen in the episode, along with the passage where a hole comes in the wall and hellish texture grows out of it as imps pour out. Great spin on the barrel-room as well. Once I got to the pentagram room, things started to change. The initial fight was easy as I merely circle-strafed the bunch of them without getting hit, and then eventually I had 200 health and armor after having found a Megasphere. At this point I ran out of ammo, but no problem as I had the chainsaw and easily butchered the remaining Cacodemons, and picked up a box of shells from the same room. As I enter a pentagram to get teleported to a platform where barons of hell and demons greet me, a really cool piece of music starts playing as I start slaughtering the monsters teleporting in. It was an exciting fight, though I only lost about 23 health and armor in it.
However, I only have about 11 rockets left and 20 shotgun shells. And now the real end fight begins. After about 30 seconds I'm out of ammo and have to kill the two giant bruisers with nothing but my chainsaw. Obviously I fail miserably and get killed the instant I try to get close. I reload to before the fight and try again. Same result. I cheat to give myself full ammo and find out the fight lasts literally AGES. I finally bring them down, though their area of effect attacks did a number on me and I have only 23 health left. But seriously, was this playtested at all? An insane amount of ammo is needed to deal with these guys, and I had almost nothing when I faced them. This was a huge letdown.
Then comes the even more real end fight. If I by some miracle managed to kill the bruisers with my chainsaw, HOW ON EARTH am I supposed to kill this guy with 23 health and practically no ammo? My conclusion is that either there's a problem with a lot of ammunition pickups being unchecked on Hurt Me Plenty and not having been playtested on this difficulty. So I IDDQD'd and used the remaining of my cheated IDFA ammo to kill him. I didn't find any of the 3 secrets in this map, perhaps they are all incredibly huge ammo caches, though I feel it quite poor that all of a sudden you have to find secrets where in the previous maps they were not needed, not to mention that the secrets didn't quite seem like very easy to spot. This is the only map where I managed to die, and it wasn't because I played like crap, but because I had to face several boss monsters with nothing but the chainsaw and no way to replenish my health.
New Monsters
I'll just quickly go over the custom monsters used in the WAD. I have no clue what they're named and can't be bothered to find out, so I'll just name them as I see fit.
Rapid-fire zombie
I guess they're cool, but despite their armor they die fast from shotgun and chaingun fire so they don't get much time to fire rapidly.
Chaingun zombie
A new twist on the commando from Doom 2, who is missing from the level set (I guess because he's from Doom 2). The chaingun zombie is a lot tougher than the commando, and looks great.
Rocket zombie
Meh, these are very rare, I think I only encountered 3-4. I suspect they pack a punch, but I didn't meet one that lived long enough to fire anything. Not sure what to think of them.
Chainsaw zombie
These plain suck. Seriously, get rid of them. For some reason its seems the Doom64 model was used for them instead of the perfectly fine chaingun zombie from the Monster Resource WAD, making them seem extremely out of place. They are placed strategically so they can make use of their chainsaws, but I didn't manage to get hit by them at any point.
Shadow
These little critters speed around much faster than regular Doom monsters, bringing a new interesting dynamic to battles. These are easily my favourite new addition. Their blur effect and their fireballs look and feel awesome. I love this monster!
Skull-face imps
They don't look EXACTLY as the other doom monsters, but they look well enough and fire some really cool homing heads. I didn't quite get the hang of how to avoid them except by making them hit a wall, as they seem incredibly good at following you. Anyway, there's plenty of cover in the levels to avoid getting hit by them, so no issue at all. They go down nicely with a super shotgun blast.
Stone imp
From the Monster Resource Wad. Didn't like them there, don't like them here either. Perhaps if they were used more cleverly or in greater amounts. As it is, I don't see a need to include them in the episode. They are a basic cannon-fodder monster and should be used as such.
Horned demon
I love these guys charging around like mad! They look great and have a really cool script. Awesome!
Bionic demon
They are tough and require two blasts from the big shotgun, and move around quite speedily. They look really cool and I loved them, especially their death animation.
Satyr
Similar to the stone imp. They aren't used enough or well enough to warrant inclusion. They work as tough cannon-fodder, but is never used as such. They make rare appearances in which they are always easily dealt with as they are alone.
Hell Baron Lion Thing
Get rid of them. Seriously, they look way too silly. I think these are from the Monster Resource Wad too. Their script is cool enough - like the centaurs they make themselves immune after you shoot them by holding up their shield. But they just don't look right. And neither do those green swirly things they fire.
Semi-doom3 styled hell knight
They look fairly cool and use those cool homing skulls some of the imps like to use as well. Generally I didn't feel they were placed in situations that made them interesting, though I think they could have.
Ghost
They were annoying as I hate stealth mobs with true invisibility, but fortunately they were few so I didn't care much.
Summary
Had it not been for the failure of the last map, this would easily have been the best map set I've yet to have played for Doom. The ingenious twists on the original maps coupled with exciting gameplay and incredible architecture and atmosphere makes this a must play for every single Doomer out there. The issues with it were, as mentioned, the final level, overabundance of armor, ammo and misplacement of health packs. Some of the new monsters were also a bit silly, namely the black imp with the blue balls and the lion-hell-baron-thing with the shield (he looked quite silly imo). Overall it doesn't matter too much, and it is still a very exciting play through. In hind-sight, I should probably have played in UV difficulty. In general, the new monsters really add to the episode and prevents it from being just the same old thing. The effort done by the team on this level set is incredible and I can't say enough how much I enjoyed playing through maps 1-7. I want to beat you guys up over the last map, though. That was a big turn-off - for shame! The levels are quite big, but the automap and cleverly used camera textures show you were to go next, so apart from my mishap in one of the maps I never managed to get lost.
But all in all, these words are just clever ways for me to say whether or not I had fun. And in the end that's all that really matters. And yes, I had fun, I had loads of fun. In fact, the most fun I've had in a long time of dooming! This is a masterpiece! And I still have the opportunity to play it through once more on UV!
PS. It rocks!
PPS. I seemed to find a lot of ammo for something called a "rifle", yet I found no sign whatsoever of anything like this. I assume it is found in the secret level and is the reward for finding it. Is this the case?