Yep, it's a good manga that I'd recommend to anyone with a sense of humor. This princess just wants to sleep well and will not care at all as to what lengths she has to go to achieve it. This sounds like it'd get boring quickly, but the author is good enough to think up new stuff to ensure it's still amusing even after well over 80 chapters.
When I say she's willing to do anything, I mean anything. Killing, pillaging, anything you can think of and more. She's also damn strong and keeps on escaping no matter how many times they try to hinder her from doing so. As the story goes along, it seems she's the one holding them hostage rather than the other way around and all the demons seemingly starts to think of her as their daughter, haha.
By the way, the universe this story is set in is kinda special, it's a truly rpg-ish setting, people can be resurrected by priests so no matter how many times the mc kills demons, they will come back quickly. She also has a habit of dying in her quest for good sleep and getting resurrected, like sleeping on top of a fluffy poisonous mushroom or going into eternal sleep by slipping into lava(although it's not really eternal since she's resurrected in a short time). The demon king and company aren't actually trying to really conquer the world, it seems more like they're having a blast playing off the typical rpg-like situation, for example, they're not going all out against the hero at all. They're actually trying to help him along and modify things so that he can keep on going, even going to the extent of giving the hero items in chests. If not for them, he'd be dead long ago, haha. Well, the princess keeps on screwing up their hard work, pillaging the items that are supposed to go to the hero or demons and more.
If I had to complain about something, it's the notes we get from the translater. The translation is actually quite good, but the notes are annoying, it's a copy-paste message every chapter about his situation and how he wants donations because of it. Something like that is enough to reduce my enjoyment a fair bit and break my immersion. I get he wants help, nothing wrong with that, but putting the notes in EVERY chapter is just too much, putting them in once every five chapters and preferably in a jpg file rather than inside the chapter so that you have to see it while reading would be way better. Maybe I shouldn't complain since I get to read for free, but it's distracting nonetheless. It's not as if they go away when you pay anyway.