Fair warning, the first episode has waaaay too much crammed into 7 minutes to make much sense. Basically the first episode is the setup one, so first they have 1 scene with the modern times, 1 scene in the overworld, and then a smash dash scene to set up the historical world....it's a whirlwind of stuff in just a blink of an eye.
However, once you get past that first episode the other episodes actually make some sort of sense and it's stupid silly entertainment.
The main protagonist somehow constantly fails his missions but then somehow wins them in the next heartbeat, he gets fired,rehired, and promoted many many times in the course of the 24 episodes.
I laughed a lot and only got confused on plot points once or twice when it was an explanation heavy dialogue reliant episode, the rest of the time it was easy to process what was happening and who you were supposed to root for.
Overall a super easy watch, funny as long as you don't take any of it seriously. This is not meant to be anything more than entertainment.
Don't look for the quality of a top 10 when you're watching a 5, although honestly I'd give this a 6.5 because I had fun.