Where do we start?

Let's talk about the art first.

The art of this manhwa is just something otherworldly, it's so good to the point I can't even imagine how hard the studio works on it to bring something so good-looking in a week. All ggs to them for that, if nothing but the art, this manhwa would be 10/10.

Enough about that, let's hop onto the story.

The story itself is very interesting and intriguing which will most likely interest you if you like Action and Game-like settings. The story progress is so nicely written which is something not many manhwas can do. The manhwa doesn't exclude many things from the novel but it has some interesting excludes, but an ordinary reader won't even know about it, it's all just something that spices up the story in the novel.
Looking at many other similar manhwas, Solo Leveling doesn't sound so original, but rather kind of generic. But that's just on the surface. The story progresses so nicely and I can promise you will not be bored or disappointed.
Not a single chapter of this manhwa will be boring, it will only make you want to read more and more and more since it's so nice and appealing.
One thing which some people will not like, where others will like a lot, is how the story, the art, and the MC become darker and darker (Not in a way of cruel and gore, but in emotions and art). I like it since it just makes the MC look more and more badass. Some people might not like cold characters, but our MC is one cold guy later as he grows stronger, which is portrayed really well by the artists.
One thing I'd point out is not including some very interesting characters more, you'll understand once you read it. There are many very interesting characters but their screen time isn't really grand.

Now let's talk a bit about the characters.

Firstly, how could I not talk about the MC, legendary Sung Jin-Woo, oooh boy is there any way to talk about him and not use all exaggerating words. Firstly, the character design is so nice, the change in the vibrance of colors in his design is just perfect since it goes well with the story. His appearance alone is enough to make people shiver in fear which I like a lot. His way of handling things is very nice and calm. He's just badass in every way possible.

Now the rest of the characters, well there are certainly some very very interesting ones, but as I stated previously, they don't get quite enough screen time. But well, "Solo" is in the title. The artists really put some effort into making all the characters, whether side or important ones, look good. So it's all on the ball.

All in all, it's so good, would recommend everyone reading it even if you're the "Ughh I hate reading those 'comics'" type.