@Blackdiamond2 It's not just you. I first noticed the older art style on page 4 of chapter 2, but the whole thing looks like it's from the 90s.
Honestly, that's half the reason I'm reading it. The story is pretty all over the place and rushed, but the art has a nostalgic feel to it. It's also pretty different from all the recent isekai and fantasy mangas I've been reading, which all look pretty similar to each other. So, this older style is oddly refreshing.
I'm guessing that the artist learned how to draw based on older mangas. Most of the issues I see here are with the weird pacing, where it literally feels like half if the pages are missing, and the translation being a bit awkward at times. Hopefully the pacing issue stems from whatever web novel he's adapting, because I'd honestly like to see a new story in this style (at least one better than this).