If you liked the Blue Gender anime, the Anime-Planet community thinks you'd like:
Thor and Rai are twins who live on an advanced space colony called ‘Juno’. Things take a nasty turn one day when they are kidnapped by the Federal Army’s Special Forces and abandoned on the hostile prison planet Chimera. A cycle on Chimera consists of 181 days of scorching heat and 181 nights of below-freezing temperatures – not to mention it is populated almost entirely by carnivorous plants. The convicts on Chimera have found only one means of survival – reverting back to the law of beasts. For the strong-willed Thor adjustment comes naturally; but for his naive and weaker brother Rai, things do not go as well. Thor must now use all his wits, strength and courage to endure life as a member of Chimeran society, rise above the rest, and take the only ticket off this planet: becoming the Beast King.
Both series deal with the survival of people on planet earth, after it has been taken over by wild plants and animals. In both cases, although under different circumstances, the main characters try to escape from the planet and the way they organize their survival is a central part of the plot. Blue gender is a bit more mature than Jyu Oh Sei, but if you liked one, it's likely you'll like the other as well.
In the distant future many things have changed. Worlds are colonized and people travel the stars freely. The GOTT (Galactic Organization of Trades and Tarifs) exists to maintain order and peace along the galaxies. Enter two ES members. Eclair and Lumiere. They are sent on missions to keep the universal peace, under the flag of GOTT. But soon they come to realize that there is more going on behind the scenes than they previously imagined...
In 2031, ancient relics were found that proved the existence of an alien race, and they bore a chilling message: mankind will eventually be fated to fight the Hadeans, and their loss would mean the destruction of humanity. Now, twenty years later, man lives side by side with mutated creatures that spawned from the waters where the relics were discovered. The Neo International Defense Force (N.I.D.F.) was formed to protect the planet from any threats that may occur as a result. Chief scientist Yuno Rukina has been sent to find the Book of the Dead. But upon finding it, vast swarms of insects and large monsters appear around the globe; the Hadeans have finally arrived. As members of the N.I.D.F. try to contain the threat, Aiba Shu is mortally wounded; to save him from death, Yuno plunges the Book of the Dead into his chest, transforming into the Necrodiver – the messenger of humanity. Armed with integrated weapons and assisted by powerful guardians, Aiba must defend the planet against the Hadeans and keep his revenge against the human who betrayed her own race.
Blue Gender and Kiss Dum are remarkably similar in so many ways. Giant creatures swarm the planet and leave a tattered landscape behind with few survivors. A lone protagonist must fight his way to survival, though in Kiss Dum the lead isn't nearly as whiny or powerless as in Blue Gender. Regardless I strongly believe fans of one would enjoy the other.
The year is 1973 when the BETA, a race of aliens discovered on the moon, first arrive on Earth and begin their systematic extermination of the human race. Mankind's only hope lies with Tactical Surface Fighters, or TSFs, piloted by both military elite and would-be trainees such as Yui Takamura, a young girl descended from a long line of Imperial Guards. Alongside other amateurs, she finds herself on the front lines of a final defense against the bloodthirsty monsters, unaware of the brutal consequence that awaits them. Three years later, Yuuya Bridges, a half-Japanese, half-American pilot, is assigned to an elite United Nations squadron tasked with developing new TSFs to beat back the alien forces. As humanity struggles to survive, Yuuya must come to terms with his biases in dealing with both his teammates' and other culture’s tactical fighters, including the veteran pilot Yui Takamura herself.
While Blue gender isn't a mech anime, both shows seem to have the same feeling of hopelesness in the face of overhelming threat. Both feature a vicious type of aliens invading earth and massacring the humanity. Both got pretty heavy theme, not only in terms of visual gore, but also psychological impact.
Ryo Takatsuki injured his right arm in an accident years ago. The resulting surgery brought about some unexpected, but not entirely unwelcome changes -- enhanced healing along with the presence of a superweapon dubbed "ARMS" in his body. But with all power comes a price, and with newfound allies who share his predicament, he must battle a secret organization trying to control the ARMS while trying to find the truth behind the weapon in his body for himself...
Both anime proves that age is irelavant factor to anme. Both anime are great pieces of work and look just as good as any up to date anime with you talking about details that you can see while watching any of anime. Thought setting are diffrend modern world and sci-fi world, both anime tells you somewhat similar storys about loss and cruel fate that makes you shoulder a heavy esponsibility.