It’s not for sure, but…well, see for yourself. There are achievements for killing enemy medics and snipers, which may describe roles for aliens and not humans…but what do you make of it? Or the Zom-B-Gone achievement?
Elite Defense and All Hands on Deck really sound like some form of base defense; maybe your Interceptor launch stations can be located and come under fire in EW.
My personal favorite is Guardian of Earth. “Designate a highly decorated soldier….” Decorated, eh? Like, with medals and accolades? I can give my soldiers medals?
Oh, and the aliens were having a mud party which I needed to shut down.