This game is great, the atmosphere is amazing and the combat is exciting. I love that there are different subclasses of opponents with different strengths and weaknesses, and the whole design of the dungeon is top-notch.
My selling point though is the story. The combination of desolate and ruined aesthetics, showing that this dungeon once used to be an advanced society, and the scattered lore books and tablets which only hint at what might have happened to it really spark imagination and make the player terrified of what might be lurking in the next room. The fact that enemies get more horrific the more you explore also amplifies the anxiety and really makes you think: "If these creatures wiped out an entire race, what chance do I have?"
Overall this is one of the best dungeon crawlers I've played, and it's just a demo! I really hope they keep expanding upon the history of Dargoth, and I cant wait to see what monstrosities await us in the second level!
EDIT : I would advise the developers to advertise this game a bit more though. Make a subreddit, a youtube channel, anything really. It would be a real shame to see a game with such big potential fail due to not enough people hearing about it!