In this doujin, based off the PSP game “God Eater”, you have some some light serving of vore and yuri, and a heavy serving of mind break, rape, and tentacles.
Story: Some years ago humanity was nearly wiped out by a group of creatures called Aragami, also known as “Gods”. The survivors make a last ditch effort by using science to create an elite fighting force called “God Eaters”, who kill and absorb the abilities of these “Gods” to become stronger. For years this war has continued.
I won’t get into the specifics, because it’ll be too confusing (God damn JRPGs), but this takes place after Mission 6, for those who’ve actually played the game.
Two such “God Eaters”, Alisa and Sakuya, get captured by the mad scientist Oguruma, who believes that the only hope humanity has for survival isn’t to fight against Earth’s new overlords, but to interbreed and become one with them. From there, we get to see these two lovely “God Eaters” ‘eaten’ themselves, in more than one way.