I found this while cleaning out some ancient Dropbox account. It's a 13k lines batch file "compiled" with some weird niche software that emulates a unix-like "operating system" (a few commands on a CLI shell).
I wrote this back in 2016 while bored as shit in some high school classroom.
It has some interestingly horrible features like storing passwords in cleartext in %APPDATA% and an ftp-based package manager - which sadly doesn't work anymore as the infrastructure powering it died a long time ago.
The boot log at the start might remind you of something. It's actually from the Hacknet hacker-simulation video game that came out just the year before, in 2015.
For some reason the color display is broken on my modern, high-DPI laptop. The script renders on a 25x80 surface.
The main prompt screen, right after login. The script creates a unix-like root directory structure at %APPDATA%\BatchOS and mounts it to a B: drive using subst, so the path on the prompt is actually the real cwd of the script.
Notice how the prompt ends with a right parenthesis ) instead of the habitual chevron >. I suspect this is because running echo $pwd$> will understand > as an stdout redirection, and I wasn't smart enough to put it inside double quotes.
Here you can see the help page for bpm, the integrated package manager. Unfortunately the http://batchos.run page hasn't been archived by the Wayback Machine... It was a PHPbb board where anybody could submit programs to be available through BPM.
I don't think anyone ever did 😅