I enjoyed this episode immensely. First of all, Dave, I totally remember those Carmen videos! HA!! I had to go back and watch them again on Youtube after the reminder, and they're just as gloriously awesome/awful as I remember.
Man, good times.
As for the story, I think Satan is best understood as the
Satanic Temple variety--which, if you like to follow news related to the separation of church and state in the USA, are those folks who want to do rad stuff like
erect a statue of Baphomet side-by-side with religious sculptures on state property, etc. I'd describe them as secular humanist activists who strongly believe in individual liberty, justice, compassion and freedom from coercion. So for the D&D-inclined, you'd call 'em chaotic good.
Satan in this story is like an incarnation of what these folks worship, even if he is on the down-and-outs when the story starts. I especially love how the story moves between stoner comedy, coming-of-age story, and civil disobedience parable. It's all of these at the same time, in equal measures, and for me it makes this story particularly successful and entertaining.
Unblinking, I totally hear you on the humor being a miss--humor is so subjective. For me, the humor worked great--I loooooove stoner comedies, and the image of Satan's nougat-smeared teeth is one I just can't get out of my head.
But what tickles your funnybone can vary so much from person to person that it's just not gonna work for everyone.