Gantz (anime) 2004

So this week I have been mainly watching the complete anime collection of Gantz, which I recently purchased from CEX down in Brighton during the half term holidays. I had previously bought 3 volumes of the manga Gantz because they were cheap at the time being second hand but all in good condition. I really like the characters and the story of Gantz. It features a collection of people who are about to die under various circumstances who are transferred to a room that has a view of the Tokyo skyline and a large black ball. Inside the ball are suits and weapons and a bald guy who wears an oxygen mask and who never opens his eyes or communicates. Nobody knows what Gantz is and it is not explained. Through the course of the series and transferring knowledge from one group of people - or I should say survivors - to the next we learn a little more each time.
The suits offer protection and give strength but they can be damaged and can fail. Gantz tells the people that their lives are now his and that they have to kill aliens in combat in order to be allowed to return to their lives. They return home after each round but are called back for successive rounds. They have an hour to kill the aliens and those who survive score points and the ones who earn 100 points will be allowed to leave. The weapons they are given are of different types: there is an X-Ray gun, a sniper rifle, shotguns, pistols and a trap gun. They fire light and have a delayed response. The main characters at the start are Kei Kurono, Kato Matsuri and Kei Kishimoto: two young men and a young woman. There is a love triangle between the three of them: Kurono is immediately attracted to Kishimoto but she is infatuated with Kato. In another plot twist, Kishimoto moves in with Kurono and this only serves to further confuse him.
It is an interesting storyline because it's not clear what is going to happen next and how it will end. I understand that the anime goes a different direction than the manga, so I look forward to the manga written by Hiroya Oku. The manga finished in 2013, after starting in 2000.