Hey, sorry to bump this, but this page is one of the first things that comes up when looking for this, and trying to find all the current information related to this can be difficult.
If you want a copy of the record, it is still possible to purchase one, however you have to purchase a copy from the company who made them directly. These records are lathe cut, not pressed.
They are, however, lathe cut into actual vinyl discs according to their FAQ. This is in contrast to the commonly used poly carbonate for lathe cut records. Will this sound as good as pressed? No, depending on what you're listening with, you could hear the difference between pressed and lathe cut. Does it sound very good for lathe cut records and even pretty close to pressed records? Yes. Edit: After contacting One Cut Vinyl, the material used is in fact poly carbonate, however I've since received the record and it sounds fine.
The company you need to contact is One Cut Vinyl, their website is here:
https://www.onecutvinyl.com/
If you order a single copy, the price is going to be a lot higher than when these were purchased in bulk. If you want to know how expensive it will be, go to their website's price calculator and enter these options:
Record size: 12" Black 1.5 mm
Speed: 33 1/3
Discs: 1
Tracks: 18
Side A playing time: 20 min
Side B playing time: 20 min
Country: -your country-
Round centre labels on disc: printed labels
Record jacket: Black card disco bag
Check "Repeat Previous Order"
For reference, all this plus shipping to USA costs £60.42 at the time of writing, or around 77 USD. Shipping to European countries is more expensive than shipping to the US for some reason, even though they're in the UK. You could also try to find others and order together, which would bring the price per piece down. On their website you can only enter 6 discs max, but if you would need more, you can write them an e-mail and receive an invoice.
You can write them an e-mail here:
info@onecutvinyl.com
and ask for an invoice for a single copy (or more) of this record. Be sure to mention that the original order was done with the e-mail address
realmmaster26@hotmail.com.
Although this is expensive, the quality of the record is quite good and they already have all the files on hand and ready to go. You're essentially getting exactly what was made here before. They also replied quite fast and were friendly.
You could of course try to find someone who will cut you a record locally with the same quality, but I couldn't find anyone who would do it at a lower price near me. If you want to go this route, you can find the files (label images and flac music files) used for this project here:
https://www.cavestory.org/music/vinyl/
Also, I thought it was a shame that this came without a jacket and I wanted a nice jacket with some art for my record, so I had a local printing company who does LP jackets print me one. I made it by scaling up some of my favorite pixel art and the logos, using nearest neighbor scaling. I saw the idea for the cover online and recreated it using the in-game art so that there aren't any artifacts, and added the English and Japanese logos.
I was worried some of the text on the spine would be too small and come out mushed together, but their printer had a very high resolution and it came out beautifully. I've attached the file I sent the printers, be aware that the positions of everything was chosen based on the template they sent me. If you want to have this printed, you might have to edit it based on the template of your printer.