So, Spider Hell.
In the original 2033, there were no spiders. There was just a single, nigh-invulnerable 'Plated' Nosalis, which avoided light.
So that entire section would be trivialized by hunkering down in a corner, waiting for it to show its ugly mug and glowing eyes, then unloading a full box from the Abzats (or, at the time 'Heavy Automatic Shotgun') into its face and torso.
The spiders are simultaneously easier, as you can feasibly kill them all without using a single bullet, and much creepier and time-consuming, so you have to balance your hate of giant arachnids and desire to see them die with the demand of 'how long will your air filters last?'
Also, unlike the ones in Last Light (and the DLC mission 'Spider Lair' which has you dragging ass through a webbed-up missile silo), the spiders here do not have the heavy chitin plates that make them immune to bullets unless they've been flipped over.
Do you know the one about the Dark Railtracer? Let's Play Metro 2033 Redux
I talked with Edmond on discord about the changes made to D6 between the original and the Redux, and it actually has a fair chunk.
Copy-pasting for posterity:
In the original game, arriving at D6 has Miller give you his spare filter for 8 extra minutes; a needed gift at that point, as the last time you had truly been able to stock up in OG 2033 was at the Hansa station with Bourbon; and 60 minutes may seem like a lot until you have to nurse it over the course of a 8+ hour game.
Secondly, Miller's commentary about 'The Soul of Soviet Engineering' is reflective of his age; The Red Army was effectively dissolved in 1991 (practically, it was just renamed), and Miller was likely 18 or 19 at the time, as part of the Two years' conscription program. That would put his birthdate in 1972 or '73, making him 60-61 at the start of 2033.
Next on the list of things that have changed, actually activating the ventilation system. In OG 2033, you still had to climb on up there, and open the four panels, but instead of twist-toggle switches, you had four buttons that you had to press, and hold, and each one was timed, so if you took too long, you'd have to start fresh and Ughhhhhhhhhhhhhhhhhh. Redux' iteration is much simpler and more realistic, as the toggle switches are what would actually be used on those starter motors.
And then we get to the combat encounter.
The oozes/polyps/whatever-the-fucks are a pain in the ass because they could overwhelm you. Moreso in OG 2033, as their 'spawning nodules' not only took between 15-20 MGR, each, to kill, but constantly spawned more oozes. In Redux, each spawning nodule is a single-use, and as Edmond showed, can be pre-empted with as few as 3 bullets, which also prevents the ooze spawn entirely. They're also recognizable to players of Last Light, as nodules are mature and up-sized spiderbug eggs with an 'internal glow' added.
Finally, the biomass itself has had only a single change; in Redux, it spits some pretty raunchy acid in your general direction, and is reasonably accurate with that crap. In the original version, it instead extended a single tentacle about as thick as Artyom to slap around the crane cab as you withdraw the regulator rods.
Copy-pasting for posterity:
In the original game, arriving at D6 has Miller give you his spare filter for 8 extra minutes; a needed gift at that point, as the last time you had truly been able to stock up in OG 2033 was at the Hansa station with Bourbon; and 60 minutes may seem like a lot until you have to nurse it over the course of a 8+ hour game.
Secondly, Miller's commentary about 'The Soul of Soviet Engineering' is reflective of his age; The Red Army was effectively dissolved in 1991 (practically, it was just renamed), and Miller was likely 18 or 19 at the time, as part of the Two years' conscription program. That would put his birthdate in 1972 or '73, making him 60-61 at the start of 2033.
Next on the list of things that have changed, actually activating the ventilation system. In OG 2033, you still had to climb on up there, and open the four panels, but instead of twist-toggle switches, you had four buttons that you had to press, and hold, and each one was timed, so if you took too long, you'd have to start fresh and Ughhhhhhhhhhhhhhhhhh. Redux' iteration is much simpler and more realistic, as the toggle switches are what would actually be used on those starter motors.
And then we get to the combat encounter.
The oozes/polyps/whatever-the-fucks are a pain in the ass because they could overwhelm you. Moreso in OG 2033, as their 'spawning nodules' not only took between 15-20 MGR, each, to kill, but constantly spawned more oozes. In Redux, each spawning nodule is a single-use, and as Edmond showed, can be pre-empted with as few as 3 bullets, which also prevents the ooze spawn entirely. They're also recognizable to players of Last Light, as nodules are mature and up-sized spiderbug eggs with an 'internal glow' added.
Finally, the biomass itself has had only a single change; in Redux, it spits some pretty raunchy acid in your general direction, and is reasonably accurate with that crap. In the original version, it instead extended a single tentacle about as thick as Artyom to slap around the crane cab as you withdraw the regulator rods.
FINAL UPDATE TIME! 
Where we save the Metro.
Journal entries for this update:
We've been locked into the 'Ranger' ending for a good while now, but even if you qualify for the good ending (the 'Enlightened' ending), you can actually end up getting the bad one: this entire level plays exactly the same for both, but once you go back to the tower after shooting the dark one you actually need to shoot the guidance system to prevent the missiles from firing, otherwise they'll still fire.
I won't be showing off the Enlightened ending, btw; that'd require me to run through the entire game again since Artyom has been a very naugthy boy during this run and...
Having said all that... that's a wrap! Both for the LP... and most likely for my LPing run as well. I never intended to 'make it' with these videos; I thought it would be a fun little project to do and share with y'all, but it has reached a point where my updates get less view time than what it takes me to record/edit/sub them and I gotta be honest, it's a bit of a bummer.
The bottom line is that at this point I'm just putting way more into this than I'm getting out of it, and that's just not a healthy way to go about things.
Thanks to all 5 of you who made it this far, I honestly hope you enjoyed the ride.
If you did, you may want to check out how Artyom's journey continues:
Or maybe you'll let me take you down a weird little rabbit hole in Inside:
So long, everyone. Take care.