This anime's story line is a bit airy. U never find out his direct connection to the aliens and why he of all people was chosen to fight but, the story has a broader focus. Dealing with the issues of abandonment and the overwhelming feeling of loneliness in a world that isn't always kind. It's touching and leaves u teary eyed. The art is also quite different then your typical anime and the setting and characters are drawn in an unusual, but fresh way. The art it's selfcompensates for areas where there is minimal animation.

This OVA would have made an even greater series if it was further developed.

Also the shonen ai bit, it's nothing heavy or in-your-face it's not even really shonen ai so if your worried about strange stuff...ect Uchuujin to Tatakaemasu is defiantly pure