My first playthrough went without any kind of bugs at all, really robust engine from what I've had the pleasure of experiencing!
There's a few super minor things which I don't know if you would class as bugs but I'll report them anyway for the sake of being thorough:
1) Sometimes when standing alongside wall tiles, the tiles will be drawn over the character, but then the adjacent tile is drawn under. I don't know how unavoidable this is with your z axis stuff, but I only really noticed this with this particular style of rock tiles at a few spots in the first segment of the game. I may not have been paying as much attention to it after becoming more familiar with the game (cause it's really cool) 
2) In the Orobas dialogue immediately prior to the bossfight, I think you may have misspelled "Psyche!", it currently reads "Pysche!"
Thanks so much for playing, it's good to hear that it was a smooth ride for you!
1) Yeah, I'd say in z-sorting all of the sprites is the part of my game was by far the hardest technical thing to get right during development. I can rearrange the geometry in individual spots to fix issues like this, but at some point I'd have to overhaul the engine to fix it entirely. I do have some ideas of ways I could rework the sorting, but time is precious and I think it probably makes more sense to spend time working on content instead. I feel the z-sorting is mostly pretty good right now, and I assume that this is the kind of thing that people will stop noticing after a while, just like how some minor clipping is a relatively accepted fact of 3D graphics.
2) Thanks for this correction. I'm terrible at proofreading. ^^;;
Sorry, I posted that by mistake before writing everything out, and now I'm having some issues with editing the previous message. I'm going to reboot and see if it still happens.
(Edit: OK, I'm back, issue still present. Here's some more info!)
OS: Windows 10 Pro 64-bit; Version 10.0.17763 Build 17763
Steps to reproduce on my end:
1) Shut down PC, remove all audio output devices, start up PC again. A small red X should be next to the volume icon in the taskbar.
2) Start 'Vacant Kingdom.exe'. The title screen will appear.
3) Press Enter, or click within the window, and the LOVE error will appear. Issue is present on both the 32-bit and 64-bit versions.
Workaround: Plug in an audio device, and the issue goes away.
Some additional context: I'm setting up an old Windows tower PC so that I can test LOVE games on Windows, and also catch up on neat Windows-only games. This PC is hooked up to a KVM switch for sharing i/o devices among multiple PCs. The KVM switch is very old, and supports only VGA for video and 3.5mm jacks for sound. When switching between systems, it looks like Windows is not always detecting that my speakers are plugged in.
All that said, this error probably won't be encountered by many people.
Ah, good catch! It's always good when people with uncommon setups try my games, a lot of times it reveals that I'm doing something silly, as was the case this time. I can go ahead and change a certain code comment now, heh.
Thanks for the detailed steps to reproduce the issue! Although, in this case it was a tad unnecessary because the crash was just me calling a method on a source instead of love.audio by mistake.
Not sure if you intend to go back and play more for the secret boss or anything, but if you do know that this crash is fixed on the itch.io release.
