It's apparently sometimes possible to fall down the elevator shaft from Descrated Cistern to Grievance Ascends, and survive. This caused me to get Holy Wound of Contrition before beating Tres Angustias, and now the Tres Angustias fight will not start. The gate from the boss room to the elevator is now stuck shut, so I cannot get the elevator activated, and can't seem to replicate how I survived falling down the elevator shaft so I can activate it from below. I can't get across the gap in the elevator shaft in Descrated Cistern, so I'm unsure if my game is now hard locked or if I can get around this (even if it means totally missing out on a boss fight).

Saves are gone. Tried to do some of what other users have tried and it doesn't work. This is unacceptable. I don't have time for this.

Go to C:\Users\username\AppData\LocalLow\TheGameKitchen\Blasphemous\Savegames and see if savegame_0 folder and savegame_0.save are there.

They're there. But I can't do anything with them. I tried to do what you did, but nothing is happening. And even Offline my saves arent saved...except when I first started. Even started the game over and can't play it unless I'm logged in to GoG. Disappointing.

You're playing through Galaxy?

Backup your saves, uninstall the game and use the offline installer to reinstall.

I ran into a bug that destroyed my progress to the point of me probably having to restart the game...at the point where you finally get to fight that doofus that follows you around at the Bridge of the Three Calvaries!
When I descended from Jondo to Grievance Ascends (my third dungeon), I lost the bile flasks, the rosary knot and other upgrades that I'd gotten were gone. Not being a spoilsport, I chewed my way through my opposition anyway, but now I've realized that I can't upgrade my sword anymore. And while my acquired special attacks still work, finishing the game on both the starting sword strength and very limited attacks seems both boring and excessively hard. And so I think I'll give this game some time for improvement and start anew. I sincerely hope that this won't happen a second time (I've read online that I'm not alone...), since I'm not sure I'd have the perseverance to go for a third round...it's a really good game, but that might be a dealbreaker. "Might" only because the gameplay is really satisfying.
I want to be angry, but it's difficult ;)

Done and done.
Finished with 99,5% completion (the missing 0,5% likely due to missing out on the Gemino quest and not having received the items rewarded for completing it) and the good true ending. Apparently I've been spared the serious game breaking issues a lot of people are experiencing.
Waiting for the first patch or update before starting another pilgrimage seems like the right course of action though.
All in all, a solid 6 out of 7 transgressions. Would blaspheme/sin again.

12) More typos:

1. 'Molten Heart of Boiling Blood' lore entry:
Wrong placement of the quotation marks there.
i.imgur.com/sG9ET0p.jpg

2. 'Mirrored Mask of Dolphos' lore entry:
Should be capitalised "Miracle" for consistency.
i.imgur.com/Pznemhi.jpg

3. When interacting with one of the corpses on the 'Archcathedral Rooftops':
Should be "In dreams" there.
i.imgur.com/iamnDtx.jpg
i.imgur.com/2CMgs5e.jpg

13) More perfectionist-nitpicking or just playing that much that I start to notice the smallest most minute imperfections in things. Note the "blip" (in front of the black background) towards the end of the ability's animation/visual effect. Could use a little clean-up.
youtube.com/watch?v=ywn86BrQdh4

14) Unbreakable 'lamp' asset in 'Wall of the Holy Prohibitions'
What it says in the description. See the screenshots for the exact location.
imgur.com/a/zjgKDgV

15) A bit hard to make out but again a case of stonework texture that doesn't line up neatly with the left edge of the screen leaving the Penitent One still partly visible while passing the doorway to the next room.
imgur.com/a/debYrov

16) Yet another occurrence of the graphics artifact/visual glitch reported earlier.
The issue definitely persists.
i.imgur.com/wY1LJ1c.jpg

I have no idea how to do any of that. And to be honest I shouldn't have to. So I tried and nope. None of my saves are being stored in my local file. Maybe some day we can get games that aren't busted.

Before any of the following, make sure that you have Blasphemous uninstalled. I guess you know how to do that at least? "Backing up" basically means making copies of files and store them somewhere safe.

1. Close Galaxy (Optional, but strongly recommended: Uninstall Galaxy)
2. Open your internet browser of choice and go to www.gog.com
3. Sign in
4. Hover the mouse cursor over your user name on top of the screen
5. In the drop down menu click on "Games", this takes you to your library
6. Look for the Blasphemous game card on the virtual shelf/shelves
7. Click on the game card
8. Look for a section that says "Download Offline Backup Installers", click on "Download Offline Backup Installers"
9. Download every listed file, and make sure that they are downloaded into the same place/folder on your hard drive
10. Once the download is finished, navigate to the place/folder with the files you just downloaded
11. Double-click the executable file (identified by the ".exe" filename extension at the end)
12. Follow the install instructions
13. Once install is completed, start Blasphemous right away from the last screen of the install application, via the shortcut on the Desktop, if you opted out of that, via the Start Menu or in case you know exactly where Blasphemous has been installed to on your hard drive, from there (by double-clicking the Blasphemous.exe within the Blasphemous game folder)

In Grievance Ascends all of the Ghost Bell Ringers in the temporarily locked rooms are intouchable a few seconds after they appear. Is this a bug, or a feature? If it's deliberate, it sure is poorly presented (also annoying).
The other ghosts in the area don't have this issue.

That's definitely a feature.
It's the same with the ones in other areas as well.

I don't think it's particularly annoying but something unique to the creature you have to keep in mind and work your way around (avoiding it for the one and a half to 2 seconds of invulnerability) in order to beat them.
It can get a little hairy if they're paired with other creatures (like the female, scantily clad apparitions with rapiers phasing in and out or the "hoppers") but that's ultimately what Blasphemous is about. Overcoming seemingly unbeatable odds and all that.

The swooshing sound they give off when they notice you and when that ends is a good enough cue for when the short period of invulnerability is over and you can start whacking at them to full effect.

Thought as much, thanks. Although, it only happens, when the ghosts appear, not if they're already waiting.

(SPOILER) On another note, and defininately a bug, when encontering las Tres Angustias: When they fuse for the second part of the fight, I never see any indicators as to where the laser beams appear. There's supposed to be a little ball first. Now it's guessing and, mostly, dying. Any other ideas?

So it doesn't look like this before the beams go off?

https://i.postimg.cc/RFzKY5q8/xptr-bl-00.png
https://i.postimg.cc/Z5Gd9tPR/xptr-bl-000.png

That's odd.
And a bug I haven't seen before.

Drivers are all up-to-date?
You could try tinkering with the in-game video settings and see if it makes any difference.
There's a bug where you can't jump down (Down + Jump) from platforms if you have vsync enabled, turning it off might have an effect on whether certain visual effects are shown or not as well.
Changing the scaling mode ("Pixel Perfect" and the other one) could solve the problem too.

If none of that helps - "git gud" and try to beat it anyway?
One of the 2 beams always goes off on the fused Tres Angustias in any case.

During my first run I leveled up Mea Culpa and the combat abilities as far and got as many upgrades (knots for the rosary, rosary beads, prayers, sword cores, etc) as possible before even attempting one of the first three boss battles.

Exactly. And I almost did "got gud", but there's always one last hit, when two beams cover almost all the screen and are impossible to avoid like this. Might try the technical tinkering then, thanks. Although so far I didn't encounter any issues (V-Sync is disabled).

17) Actually the first typo you come across:
Should be 'Deogracias' (minus the 's').
i.imgur.com/keq295x.jpg