An enjoyable read.
There are a few inconsistencies, a few slow downs but overall, it's well paced and the philosophy holds up. I honestly think the beach arc was one of the best of the genre.
I feel like at some point, this kind of "survival/philosphical" manga was very popular, and now it's been replaced by a stream of isekai type of mangas/manhwa.
In my opinion, both could appeal to the same group of people, i've just got the feeling that the majority of isekai mangas are a lot less profound and overall, more oriented toward a younger audience.
It's an 8/10. The art is good, the characters are well written, the story is interesting and there's lot more to it than simply what's written (most of the trials are metaphors).
I read it in 2 days, quite the binge.