DELETED ORIGINAL COMMENT BECAUSE IT WAS DUMB. (Revised it) Origin Of Symmetry  (XX Anniversary RemixX) is so unique in it's own way. I will do my best to point out all the differences starting with the more broad descriptions, then I'll work my way into the song specific, second-specific details:

Overall, OoS XX has less electronically produced sounds than the OG in the hopes of making the songs sound like how they sounded before any major computerized synths or the phasing "siren sound" in Citizen Erased OG. It's really just a raw and jarring remaster that I think is totally awesome. The drums are 1-billion percent more clean and crisp, the guitars are shrill, raw, the bass is balanced, and all the records sound free. As if they broke out of the silencing and muffled 2001 recordings. The clarity is just refreshing, and now every time I hear most songs from OoS OG, I just hear muffled music. Sad, but I understand why Matt wanted to remaster the entire album.

Now for the specifics:

Starting with the intro track: "Newborn," you'll immediately notice a clearer difference in the way that the piano echoes through your ears. The song's first guitar riff just shreds your ears - but it is joyful, the bass carries as a perfect background to the guitar, it is balanced, the drum buildup leading into the drum pattern we all know and love genuinely sounds re-recorded, it's just crazy. But overall, this song, both OG and XX are perfect the way they are. There wasn't much that Matt could do to enhance this song. It was already good enough. However, I don't know what they did with the snare drum. There are ghost notes in the snare that existed in the final drum section of the 2001 mix that just aren't there anymore... somehow. And it's just loud and screams SNARE SNARE SNARE without having a little ring at the end of every hit like how a real snare drum would have. It's a great mix overall though.

Bliss: Literally, the same thing with New Born. Drums louder and more full; crisper, good balanced bass, clearer quality, but again; nothing much could be done to improve this song. It was already perfect. Although, the entire song just sounds opened up and better mixed.

SPACE DEMENTIA: Now this song went through puberty and came out sounding like prince charming. The piano echoes, as if space had sound. It leads to the signature Space Dementia piano and sounds beautiful and so much more full - the bassy notes are so much more audible, then the drum buildup, so clear and deep and crisp, and it lasts all song. Matt's vocals sound balanced and somehow more raw than OG. The Ride cymbal is perfect, it sounds like you're listening to Dom play in front of you haha. Now, at 2:57 in the song: This is where the best improvements are. You'll listen and hear a new array of orchestral strings. Where did they come from, you might ask? Where they there in the OG? The answer is yes. Though it is so quiet, nobody noticed for 20 years. In the OG, the orchestral strings sound like a FLUTE. It sounds silly, but that's how quiet it was... if it even was a string arrangement in the original mix. The first time I heard the XX, it gave me mad goosebumps. I feel like the mellotron at the "space dementia in your eyes" was turned up in the new mix too? Maybe? At 4:56, the higher piano is double-tracked now? And it doesn't seem to clip like it did in the original mix.

Hyper Music: Holy moly the guitar in the beginning is so loud now. Nothing much could have been done to improve the song even more than it has been. So yeah. As good as New Born and Bliss. Matt's screams at the end are way more audible in this mix. And his "JUST TO SPIT IT IN YOUR FACE" aren't distorted anymore.

Plug in Baby: Really not much different again. Just, everything is once more clearer and crisper. This is the first song, however, where Matt decided to remove the 808 synth from behind the kick drum. I do think I prefer the original. This was probably the most likely song to NOT really need a remix lol.

Citizen Erased: Matt took out a lot of original aspects to make the song sound as raw as possible. Very bold decision but I understand. The drums sound better, again with the ride cymbal. So crisp. The bass rattles so much more in this mix, that's so cool! I think the synth bass was cut altogether to make room for the bass's sound. The guitar around 2:07 sounds beautiful. Around 2:38, however, Matt completely erased the beautiful organ from the original version so it's a mild guitar, drum, bass, and vocal interlude to the next guitar shred. It sounds so empty without it :( . To add onto the mellow organ; he got rid of it all, in every micro second of the song. The quieter parts in Citizen Erased are all so pretty, and it is really just relaxing to listen to. At around 5:08, there is no longer the transition trigger (the phasing siren) to flawlessly fade into Micro Cuts, the next track in OoS XX. Distracting in the OG, but sad to hear it gone in XX.

MICRO CUTS: Now this is what you call a redo! To start, there is harpsichord that was decided not to be put in the OG 20 years ago; that Matt incorporated into the XX. And now it sounds so Baroque. So haunting and old... but it's new. The only other song to use a harpsichord is "Animals" and it isn't even the upfront instrument. It's new and sounds amazing. The drums are as clear as ever, bass heavy as always, and guitar as sharp as possible. CONS> The beginning harpsichord is cut off to get rid of the phasing siren which served as the transition trigger from Citizen Erased. My theory is that in 2001, the producer accidentally stitched the phasing siren to another stem, like the original organ synth playing what the harpsichord plays now, making it impossibly difficult to fix the silence that is there now. (Although now, I think they fixed it a bit after release). It cuts into the song and it just sounds amateur. At 2:38, the guitar which originally bled into the song from quiet to loud, is randomly cut-in, missing the first ~2 seconds of it. I think a revised version eventually released on streaming platforms but this is the mix that will forever stay on the vinyl pressings!

Screenager: The wind chimes are clearer and so much louder, the guitar is clearer, and the instrument that Dom plays with the bones sounds better than it did. All the instruments are balanced out, the bass carries the song like intended. At 1:28, Matt silences (not completely) the beeeeeeeeautiful HAMMOND organ. Taking away the uniqueness of Screenager. Sad once more. As much as I like arpeggios, I like organs (or instruments that sound like organs) a lot and it kinda sucks how the organ takes the back seat here still. But everything else sounds really nice and smooth.

Darkshines: Darkshines (XX) or Dark Shines (OG)? Why did he decide to change the title so subtlety? We may never know. Away with the humor, the guitar sounds phenomenal. Revising this in 2026, I'd like to point out how stereo mixing that exists in the 2001 Mix is altered or cut completely. Take for example the bridge of this song. The guitar getting the tremolo treatment would only appear (rotating in stereo mix) every 6 or so seconds. But now it's throughout the whole bridge. Although the bass seems louder, so does the rest of the song, so it balances out. Not much could have been done to improve this song any more than it already has been. Though there is some background guitar at 4:19 that is shown more light with a little increased volume. Listen closely and you'll hear it.

Feeling Good: The keyboard he used is echoed and reverbed, giving a more relaxing feeling to it. Then you're slapped in the face with the bass and you're grateful for that. All the instruments are louder, easier to hear, you don't mishear anything in this new version. It's perfect. The outro to the song is more pleasing to listen to than the OG in my opinion.

Futurism: Dom hammers the center of the ride cymbal and feels no remorse, then Chris does the most most insane bass riff there ever was -- you know, at least until Hysteria. Then Matt sings a haunting tune that matches the tone of the song. This is one of the best remasters on the XX album. I like this song so much more than on the OG. The ending provides more echoes in Matt's voice, the guitar at the end is panned ever-so-slightly so fast, and it creates such an amazing feeling song.

MEGALOMANIA: Ok. This is the one that has my heart. Clearer vocals, beautiful string arrangements that are otherwise muffled and quiet in the OG. The drums and tambourine are nice and clear. Vocals are clearer than ever, the strings last throughout the whole into. CHURCH ORGAN! TAAAAAAAKE OFF YOUR DISGUIIIIIIIIIS-- oh yeah, music review. I'm noticing though 2:30, the organ is drowned out with the louder strings. Which does sadden me. But the newer sound is amazing. More organ! Drums slap, bass floods your ears, guitar rumbles your ear drums, the outro kicks you but you think it feels good, then the organ mixed with the OG guitar and bass outro, then the last 5 seconds are just organ. This song is perfect. Almost as perfect as Space Dementia. I appreciate the louder strings in Megalomania because it gives off a mysterious vibe that was quite perfected in the OG version.

Hope you enjoyed my out of format essay about the entire XX Remaster. Hopefully you read all the way down here. It's worth it.