Want to preface this having read the entire series in the span of 3 days, so its still pretty fresh in my head.

I'm very big on story and how deep it gets, I was expecting Gantz to be something like that but I left it with feeling like I missed something or at least I didn't care too much about its overall story. I would say the overall theme of the entire of manga is basically just "never give up" I don't want to spoil so I'll try to keep it as spoiler free as possible.

Basically the story revolves around a character named Kurono who is a teenage boy and the only thing on this mind is basically just getting a girlfriend and watching tv. He's got a very standish off attitude towards everyone and only really cares about himself, there is some character development with him but not as much I would like. He has to basically protect Earth from aliens tasked from a mysterious black ball they've named Gantz.

Characters are super important to me since we're following a group of them most of the time, I left the manga not really having a favorite at all besides like the man and the child he adopts, but he never gets any greater backstory so there's not much to invest with him. All the other characters are just really only there to support Kurono and don't really do anything more than that. All characters are really shallow and barely have an actual personality, with each character you can basically say like two sentences at max to describe them.

The things that kind of ruin the manga for me is that the story itself had a lot of potential I believe to be more interesting, especially with nearly 400 chapters, but its really surface level and in my opinion doesn't offer much afterwards once you finish it. I wasn't a fan of the bit romance aspect in the series either, I may be being brunt with saying the story is surface level, but the little romance they have in the story is actually surface level. All romance scenarios are exactly how its played out "i like him" -> "i love him" ->"we're together now" is that really important in a series like Gantz? Not really but its really annoying to see with the characters cause there's no foundation to be built for relationships between character non of the characters have a real reason to like another character realistically and I could MAYBE understand it with child characters (14-16 years old) but it also happens with adults as well.

Some more about the story that I personally didn't like, once you find out the main mystery and main antagonist of story, it really just feels like the they put in these plot points out of no where to explain everything going on, there's no greater answer or meaning to be found within Gantz , they just put it plainly "this is why this happens and this is why that happens" there's also just a few random things that get arcs that never get explain?

Spoiler, click to view

THERES LITERAL VAMPIRES IN THE SERIES THAT GET A WHOLE ARC, in a story about fighting aliens with high tech armor and suits, and then just vampires, and they don't explain anything about their motive its just vampires. They also just fuck off after their arc is over like what???

Gantz was made in the very early 2000s and I feel like it grabs a lot from that era in terms of its edginess spoiler ahead in me needing to explain its edginess

Spoiler, click to view

there is a character that does literal black face and i mean black face to the degree where he actually looks like a black man from America and does a mass shooting in the city and gets away with it, he is never really punished for it, on top of that there's also a school shooting to show one of the side characters back story

even with its edginess I actually really like how characters from different countries look very different from each other for the most part, but for the most part you can feel how dated some of the material is with its writing of characters.

The art starts off really good for the first 150 chapters and but really bogs down a bit in later action scenes when they implement 3D CGI into some more important fight scenes. Some of it is honestly a bit intelligible to read and some of it also looks really bad imo, I get using it for more unimportant scenes so more effort can be put into important scenes but I feel like towards the end they used it a bit too much. Here's an example of a panel towards the end of the series

Even with the more frequent inclusion of CGI towards the end, there is still a lot of great art and scenes to be viewed towards the end.

TLDR
All in all if you're looking for something more really high octane and fast pace then I think Gantz is great, I had a lot of fun reading it honestly, its just afterwards with 380+ chapters I was left the feeling of "that's it?" non of the characters are really likable besides like a two or three imo, there's a bunch of random things that don't get explain, the characters motives don't feel real to me , especially knowing that some of them are just 17

STORY: 5/10
ART: 7/10
CHARACTERS: 3/10