An elderly man and a sociopathic teenager are accidentally rebuilt into unstoppable alien machines. While one chooses to save lives, the other uses his new weapons to purge society.
Why it's similar: This is the definitive successor to Gantz because it shares the same creator, Hiroya Oku, and his signature hyper-realistic, cynical urban aesthetic. It captures the same feeling of ordinary people suddenly wielding god-like, incomprehensible alien technology.
Power comparison: Characters use internal cybernetic weaponry like finger-guns and flight rather than external suits. The mechanical detail is just as obsessive and terrifying as the X-Gun mechanics.
Why watch after Gantz: Watch this if you want the exact same visual style and unapologetic violence that made Gantz a cult classic.
