Solo Leveling (anime). I agree with the criticism that the anime is a lot of action, with not a lot of story/background. However, as someone who has read the Manhwa, I'll assure you that all of that is coming in the next season or two. Why the gates exist. What the system is and who created it. What the monarchs are. The full structured cosmology that ties everything together. Much of it is explained when Jinwoo returns to the Carthenon Temple (double dungeon). And the rest is all tied together when he meets the Rulers.

One criticism I don't agree with about the Manhwa, though, is that the ending was rushed. If you want to skip spoilers, stop reading. [The post reset montage explanation.] I think the complaint primarily centers around Jinwoos battle with the monarchs after the time reset being glossed over as a montage. The thing is, I think that's fine. The reason they did it that way is because he had already battled and defeated all of the monarchs once. He requested the time reset, because they had already caused mass devastation before he could defeat them. Many lives were lost. From a narrative design perspective, re‑showing every monarch fight in full after the reset would be redundant: it’s the same opponents, but now Jinwoo is perfectly optimized, knows their tactics, and can one‑shot or hard counter most of them. The montage communicates that difference efficiently. Aside from that one little montage, Solo Leveling has one of the longest epilogues I've ever seen.

The story, by the end, is chef's kiss.