It's a comedy about children in elementary school.

We have 2 brothers riding around in their Hover bikes. Suddenly some giant Metal Fortess gets in their way. After a brief battle, the duo manages to mortaly wound the fortress. It retreats and dumps our heroic pair in a seemingly wasteland. 
But the wasteland is inhabited by nomads that indicate that the fortress has hidden inside a mountain. The Nomads plead for the duo to finish the job. Two of the natives go with them as guides, and somewhere along the way the gain the help of a faery that can transform into a mech-warrior woman. 
(Source: irreality.org.uk)

Futari Gurashi follows an aspiring manga-ka called  Kenji Aoyama, when he meets a boy called Saitou Hikaru. However it turns out that "he" is actually a girl who was raised as a boy.

Kuro is just an ordinary cat who only wants to protect his owners who are an old couple that can't fend for themselves. One day while on a date with his girlfriend Pooly who is a dog, he is kidnapped by an evil scientist and turned into a robot. Kuro somehow removes the chip that controlled him and notices that people get scared with his new robotic appearance and that he can now talk like a human. He decides to disguise himself with the skin of a stuffed toy and to continue living as a pet.
 
(Source: Anime News Network)

Studio Bogey