1. As a beginner at the time branching out to read those genre of stories, SL was super easy to read. Plot was not overly complicated and easy to follow.
2. Action scenes were very nice.
3. The art was spectacularrrr.
Back when it first came out it was one of the only ones in that particular trope/sub genre and yet it never failed to stay at the top by not introducing some weird harem or making the mic hella dumb or weird. The art style is also pretty good. The pacing, plot, and side characters are also decently developed.
I only started reading it after the anime came out but I've been hearing the hype for the manhwa even before it was completed. I think it's just satisfying to see him grow so strong. He act precisely and don't do stupid shit lol
Also the plot explanation is easy to understand, the author managed to make it easy for reader to enjoy the plot without frying their brain.
And this is just me but I love the shadow armies. They're funny and very expressive even without talking.
I started reading solo leveling when it only had 50 chaps released. I just couldn't get invested. Would you explain me what made you hooked to that manhwa?