I really love a lot about this game and the aesthetic is great, but I did want to echo some of the things louve said and chip in my two cents if it's ok as someone who has spent a lot of time in DOS.
Having to type .exe does throw me off but hopefully that's an easy fix. Fixing the tab issue might be a problem on the website but as someone playing the downloaded version it would be a very nice QOL improvement.
You mentioned you were going to add in the "man" function for command help but I believe that's the UNIX way of doing things and doesn't exist in DOS, where as louve said the expected way is "HELP FIXTEXT" or "FIXTEXT.EXE /?" both of which I instinctively tried and was disappointed they didn't work.
Thank you for this amazing work, I'm going to make sure to show it off to as many people as I can!