This review also covers part 2. There is no part 3 yet, as the author has been conscripted into the military. A continuation will probably have to wait till 2021...
The Dungeon Master is a rather weird "reincarnated in a different world" story. Not only is it Korean, but the plot also jumps in the weirdest ways. The only story-focused comic I know that makes weirder jumps is Fire Punch, the manga that spawned this very fitting meme:
Anyway, it's definitely not as crazy as Fire Punch, but it is close to impossible to predict what will happen next. The rough world our MC is thrown into, has some vague mysteries, but at the start you don't get all that much info about the world, so they're adressed very slowly while still managing to be engaging. The MC is also not an overpowered god-like being in his new world, which is a breath of fresh air after seeing all those wish-fulfillment isekai manga.
The mention of weird jumps in the story might make you think that most of the characters will be bland or onedimensional, then. However, I found most of them to be rather interesting. Almost all characters that have any real impact on the story, have intriguing and more "hidden" sides to them. And the development of the MC's mentality is handled really well.
Saying more about the story is not only hard, but would also most likely spoil things that are better left unspoiled.
As for the art: it's good. The art isn't godlike, but it's definitely up there in the list of good-looking manhwa.
Give it a try, if you're prepared to handle a long wait before the story continues - if it ever does. Alternatively you can give it a try to check out the weird storyline.