Café de Nuit

Hi! I'm a newbie DM about to design my first dungeon (I've DMed before, but my former games were in other settings).
1) Any advice? I already watched Pointy Hat's video so I know to give the dungeon a theme, to balance combat, puzzles & roleplay and to make sure puzzles have more than one solution. But anything else? Anything special to notice in a horror dungeon?
2) Is there any 'dungeon builder' website I could use to facillitate the process, or should I take out my pencilcase and start sketching?

Comic book author, Kieron Gillen, once designed an RPG to go along with a RPG-themed comic he was writing.

(the comic and the game were titled, DIE, and in my opinion both are well worth looking up)

Anywho, he once wrote a bit about his game design theory, and I found it very helpful.

Gates, Chests, and Keys.

His advice in the article is more about pacing and the plotting out of an adventure ... but the concepts transfer equally well to dungeon design.

The only other piece of advice I would add is to never lock the ONLY way to advance the story behind a roll of the die.

An example might be hiding the final boss / way out of a dungeon behind a secret door or something ... because if the Scooby gang does not discover the secret door ... now what?