I am intrigued by the US translation of the terms. Of course, Wels, or Werusu, is the katagana reading for the English word Virus. And the facility where mutated people are pressed into food--it is the soylent system, after the movie Soylent Green. (The famous quote, "Soon they'll be breeding us like cattle! You've got to warn everyone and tell them! Soylent green is made of people! You've got to tell them! Soylent green is people!")

How about all the "angles" or tenshi you fight in the end--a straight quote from Eva. There are certainly many references, The water Element soldier Kelvena loos lies Ayanami Rei, for example. And the whole Gundam based neo-type, examplifed by Elli's gear ability that looks like a "funnel" system linked via psycho frame.