Yes, and it's only the beginning. If you are watching the anime, i totally recommend you to read the manga later, since the anime has its own ending; and its shit.
Even though you may not read manga, i'm sure that you won't be disappointed with Gantz :]
It goes on after ep 21, and it's the best thing you'll read in 2017, one of my favorites mangas btw.
Watched 5 centimeters per second. It was kind of a boring movie. Half the time I didn't know what was happening and who people were. Is there anything that continues after those "3 episodes" that make the movie? Or am I stuck with pointless questions?