The year is 2025. Fifty years ago, Queen Himika and the evil Jama Empire attacked mankind; Kyushu, Japan, was their battleground. Ultimately an event caused fog to surround Kyushu, effectively cutting it off from the rest of Japan; and the mainland has lost contact with it ever since. In the present, students like the motorcycle-loving Kenji Kusanagi have little knowledge of these events, except what they learn in history books. However, when Himika and her Phantom Gods appear once more, Kenji finds himself in the middle of the battle - and a cockpit. Now, as the pilot of the mecha Jeeg, Kenji and a few unlikely classmates must battle the forces of evil and save the world!
In the year 1988 Jinki model enthusiast Aoba Tsuzaki is kidnapped and brought to Venezuela, and soon discovers that not only are Jinkis real, but that she will also become a Jinki pilot. Fast forward to the year 1991, and a series of unexplained events known as the Lost Life Phenomenon has been wiping entire cities out of existence. Enter Akao Hiragi, a young girl who has lost her memory and also has a strange tie to the Jinkis. Combined, Aoba and Akao have a common enemy: the evil Kokushou, a man who is hell bent on destroying the world!
Jinki Extend and Jeeg have a few things in common: they both have piloted mecha (big deal eh?) and characters who were somewhat thrown in the middle of a war they weren't expecting. Neither of these elements is terribly unique, but in general the two anime have a very similar (and somewhat campy) feel, and have an overall sense of genericness. Jeeg is definitely the most upbeat of the two, but if you liked one you may enjoy the other.
Akira Kamui, Ai Kamui and their father have a serious problem: debt! Akira and Ai steal a family heirloom treasure map to keep the spoils for themselves, but an unfortunate distraction occurs: their city, Chitose, becomes the battleground for the military and an invading race of aliens! Falling into the lair of the treasure itself, the giant mecha Tri-Zenon, Akira, Ai and their friend Kanna now find themselves in the adventure of a lifetime: protecting Earth from the powers of Zenon Palace!
Humanity is under attack by the Oni - fierce demons of unknown origin - that can only be defeated by Dr. Saotome's Getter Ray-powered robots. However, these robots are only a stopgap, buying time for the next generation of Getter-powered robot: Getter Robo. Able to change shape into three combinations to suit the current task, and vastly more powerful than its predecessors, Getter Robo requires three pilots to fully utilize it. Dr. Saotome selects three interesting individuals for the task: Ryoma Nagare, a headstrong martial artist; Hayato Jin, a power hungry terrorist; and Benkei Musashibou, a bear of a man who has turned to the way of Buddha. Together, these oddly-matched teammates must find out where the Oni come from and stop the threat that they pose.