This is frigging great. Solo Leveling, One Punch Man kinda great.

The start is very boring and slow paced, it's about a teen that has a perversion for books, he does nothing else, so when he couldn't cope with not having enough money for more books he started playing a game where there is an actual library. What does he do in the game? Well read books of course... about 15 chapters go like this with some minor intermissions.
However, once the MC starts having to do quests to expand his available cache of books the story takes rhythm and it's actually not bad at all, well, at least when the current conflict with Demon started it got interesting.
Other than that, the MC is the only real focus here, there are hardly any other char worth mentioning and most are NPCs. Story is as told before, mostly unappetizing, same for pace. As for art, it's in the lower strata when it comes to manhwas, it's serviceable enough so I don't really care, I always find characters, story and dialogues more important.
So, so far mediocre but it's getting better and right now it's quite interesting. If the MC goes back to reading books after this well that will be the end of it for me.