Gantz is the strangest thing I've ever read. There are so many twists and nonsensical developments that Gantz feels like 3 or 4 separate manga sown together into a Frankenstein's monster of craziness. Powering through the large plot holes was a battle, but marveling at how they managed to complete this ecstasy hit of a plot was worth it

Story:
Honestly what the in the f***? Gantz starts off as this cool, macabre, version of Men in Black, then takes a wrong turn into Hellsing territory, before finally beaching itself in Independence Day. The story isn't so much confusing as it is baffling, which weakens otherwise solid action sequences. To describe it in one sentence, it felt like I missed 3 context-giving arcs and was thrown into the deep end of the pool...

Characters are built up, only to be brutally murdered by some off-the-wall monster like some sick combination of Game of Thrones and Stephen King. No one is safe, which has this odd effect, the inverse of plot armor, where a reader doesn't get attached to anyone because they'll be sauteed by a sentient Buddha statue with swords for arms next chapter, probably. There's no problem with this, in concept, it sets Gantz apart from other manga, but the problems arise quickly.

As the plot takes an acid trip, the character deaths do too. Nothing makes sense anymore. Even when they try to explain what's going on, it takes a heavy prescription of Suspend-My-Disbelief to just accept what's happening. I wish they'd have ended the story about... 100 chapters sooner than they did, to spare everyone the utter nonsense that occurs in the last 1/4 or so.

Art:
Gantz is not new, the first chapter is over 10 years old, and the style reflects that era; it'll take some time to get used to it, coming from newer things. Once that happens, it's not half bad, though I found some of the action sequences to be a bit hard to follow.

Character:
Kurono Kei develops tremendously as a character from his rather pathetic beginnings. Gantz counters his Deus Ex Machina determination with a brutality not usually seen outside manga like Berserk, and it's that constant fear of death that drives the reader to care. The rest of the cast is pretty flat, not really developing beyond what they were presented as initially. They pretty much all fall into one of the following descriptions: arrogant asshole, sociopath, normal person, or woman.

Enjoyment:
I enjoyed Gantz because of its off-the-wall action, without that it's hard to recommend. There are better manga for character development, plot, dialogue, and frankly violence as well. The juxtaposition from the beginning and the end is second-to-none though, there is NO WAY to predict what Gantz becomes from its first chapter.