I grew up with the C64 version of Demon Stalkers, I consider it to be THEE version. The DOS version is a totally different game altogether (totally different levels and pace) and isn't the game I recommend (but it still looks enjoyable)
The C64 version I think is incredible and genius. You need this password puzzle wheel to progress through the game, but I have seen it available online through a txt. document. It's one of my favorite games of all time, 101 levels of greatness with a true storyline and ending, epic final boss that legit gave me nightmares as a kid (Calvrak), with sprites and textures in the 100th level that are found nowhere else in the game, and has a SICK level editor for endless replay. Definitely check it out if you like Gauntlet. Seriously, nobody knows about this game but it was my favorite as a kid. We played it more than anything at my house. I still have my childhood copy and manual, plus a separate CIB copy with the wheel that I bought on eBay.
Funny enough, we owned Gauntlet for the C64 too, but it was our only floppy disc that would never boot up, I never recall playing it, yet even have a photo of myself from 1993 where Gauntlet is the disc in front of all our games