I've been playing Afterbirth these last few days. I got Dead God like a month ago and I was experimenting with mods to try and recreate WotL (Rebirth of the Lamb, Eternal edition, Reflashed, only standard size rooms, etc.) but sadly all of the mods were either incomplete, obsolete or had a incompatibilities with each other; I was tired of dealing with that so i decided to go get my old-ass Afterbirth save from 2016 or so and get Platinum God in it and the experience was shocking.
I didn't remember everything being so easy, it's probably because the enemy bullets travel faster in Repentance and the item pool is bloated to shit in Repentance (719 items in total) compared to afterbirth's relatively modest item pool (436 items in total). I immediately tried out Greed mode and completely demolished it with all the characters I had unlocked at that point, my Greed machine counter was at like 108 before being abandoned and I got it to 1k in 2 days (picrel). I used to waste so much fucking time in this mode and it felt impossible back then, I even skipped on studying for some exams because a run looked promising and now I'm just going through it like it's nothing. Did it with The Lost as well as soon as I got the mantle (I didn't even have to use it against Ultra Greed lol) and then with Keeper as soon as I unlocked him, although that one took quite a few tries because I kept getting shit tier items, so I really don't have to touch Greed mode in this save again, thankfully.
Another shocking thing that I didn't remember at all is how Chaos used to work and how dogshit it was. In Repentance Chaos turns every single item pool into one and then everything draws the items from that giant pool so with 719 items breakfast only happens on a busted run. In Afterbirth, however, it seems that instead of doing that, Chaos draws from a random item pool instead and since all item pools are way smaller you're gonna get breakfasted really quickly, specially in Greed mode where it only takes one or two floors.
The D4 got a similar rework, in Repentance it rerolls every item individually and only among the same item pool you got it from (general one with chaos) and items you got and rerolled are marked as "unseen" so you can find them again if you rerolled them (and you can reroll into them again if you continue rerolling) but in Afterbirth it rerolls every item into every pool, not only that but it marks the items you get as "seen" so not only can you not get them again but you can't reroll into them either and with every reroll you get one step closer to getting breakfasted.
Another thing that had completely left my mind, probably to cope with the horror, is the special item system that used to be the standard until Repentance changed it to the infinitely superior Quality system. I didn't remember what the game considered "Special items" until I checked the wiki and was disgusted as soon as I saw the icons. Imagine getting cucked out of Sacred heart, Brimstone, Godhead or even Mom's knife because you saw (not even took, SAW) the fucking Ludovico technique or D100, it'd be funny if it wasn't the standard until 2021. Also it's worth noting how Soy milk, Lil' brimstone and the Stop watch were put on the same tier as the run-winning items mentioned previously.
Another much needed rework was the way the Angel/Devil rooms worked. It wouldn't have been a problem if Mega Satan didn't exist, but having to rely on winning a coinflip or getting Dad's key to fight him is infuriating. You can't guarantee an Angel deal next time by skipping the first Devil room, either, only way to truly guarantee is through the Sacrifice room, and The Lost has no access to that so you're stuck with Dad's key or the coinflip with him, so good luck if you got an insane run and only got a half of the key because that entire run was for nothing. It doesn't help that Angel deals are pretty shitty pre-Repentance and only worth visiting if you're risking it all for Sacred heart (or Godhead if you've completed The Lost).
And talking about The Lost, it's insane how much they buffed him in Afterbirth compared to the base game. In the base game he lacks spectral tears and don't get any starting item, not even the shitty D4, so you actually have to go through the entire thing without getting hit once with no advantages outside of flight. Even Tainted Lost in Repentance is easier because he makes it so HP items and the like never spawn but with base The Lost you have to deal with all the base Rebirth bullshit completely raw, including the complete randomness of getting to Mega Satan. The Holy mantle makes him easier than even WotL Blue baby, and since Repentance also changed his D4 (you'll never roll that shit because it removes your mantle) into an Eternal D6 (D6 that works like the one in WotL, has a chance to make the target items just disappear instead) and paired with the mantle you basically have a discount Isaac with infinite health. Any person who got Godhead as base Lost is an actual master and the game and this reputation stuck with him for years to come because I remember people treating him as the ultimate challenge of the game when he's a pretty exploitable character compared to Keeper who is the designated challenge character of the DLC and was pretty hard until they reworked him in Repentance. I guess people trying to beat Delirium in AB+ and getting telefragged in a second kept the flame of his rep alive, even if it's just because Delirium is some of the worst that has ever touched the franchise only next to Ridiculon's music.
I used MissingHud to track my stats, it's actually the first time I've ever modded Afterbirth because I used to play completely vanilla back in the day. I downloaded the charge bars mod as well which was implemented into the game by Afterbirth+ if I'm not mistaken, I wonder what other QoL stuff that I take for granted now can I put in the game.
One thing I actually dread going back to is Ultra hard. I could barely even complete it in Repentance with a Q4 starting item >>791 so I'll actually have to restart over and over to get something decent yet again. At least the annoying Repentance room layouts didn't exist here yet so it may not be that bad, all things considered. The other challenges are piss easy now and didn't even take more than the first run in some cases. I even speedran Slow roll because you are OP from the start and I got the Shovel in my first Devil deal so I shoveled my way to Depths 2, nuked Mom and beat the challenge in 6 minutes (I forgot to save the screenshot I took like a retard).
Playing with the roster of Isaac clones felt surprisingly fresh, probably because I just came from the gimmick-infested hell that is Repentance. Sometimes I just want an Isaac with different stats and play through classic room layouts, but I already have Wrath of the Lamb for that, I guess (not base Rebirth because it sucks dick).
These are my current thoughts on Afterbirth after revisiting it 7/8 years later, but only my initial thoughts since I've covered most of the basic stuff.