If you're looking for anime similar to Armageddon, you might like these titles.
A group of young space cadets use a technologically advanced mecha to combat an evil extraterrestrial race that is trying to take over the galaxy.
Wonder Princess is an Alien on the run from a rival alien race, who arrives on Earth, and ends up doing battle against them there. But not before befriending a handsome astronaut.
It is the year 2113, and mankind's reach has extended to space. After the mysterious destruction of a space cruiser from the alien planet Elysium, a full-out attack is launched on the unsuspecting planet Earth, causing much death and destruction. Now, the fate of the world lies with 4 knights, and their ability to wield ancient relics buried deep beneath the Earth's surface. With Elysium's force pressing closer, and Armageddeon upon them, they must fight to save Earth.