Dyogrammaton
English title: Dyogrammaton
Japanese title: ジオグラマトン
Type: OVA
Source: Visual novel
Episodes: 2
Status: Finished Airing
Aired: Dec 15, 2006 to Feb 23, 2007
Duration: 22 min per ep
Rating: Rx - Hentai
Studios: Azeta Pictures
Producers: Discovery
Licensors: Adult Source Media
Genres: Hentai

Based on an adult game by CLOCKUP 

An enormous monster appears and attacks the city, only to be thwarted by the amazingly voluptuous superheroines! Explosive action, dynamite sex scenes and battle royales take place in this futuristic flight of fantastic proportions that will make you cream in your pants!

(Source: AniDB)