Two weeks have passed since Earth Defense Force 4.1 received Time of the Mutants, its first DLC pack, and already there is a second one available. While you certainly won't see me complain about games getting more content, Earth Defense Force has taken things to the extreme by nearly doubling in size within the span of a single month.
As for the newly released Mission Pack 2: Extreme Battle, it contains 23 new missions that will have you face off against every bug, robot and battleship the Ravagers are capable of mustering. More importantly, however, these missions are supposed to be some of the toughest challenges you'll face, so if you do decide to play them make sure you're aware of what you're getting into.
If you're interested in some actual details on Mission Pack 2 I'm afraid I have to disappoint you as there simply aren't any. The EDF devs aren't really the talkative type, and as such the DLC description and announcement are both a single line of text. As you might imagine, they instead prefer to communicate through the medium of bug smashing.
I haven't personally given Mission Pack 2 a try, but I did check out what the community seems to think about it, and I glad to say that its mostly good news. While its nothing special, Mission Pack 2 brings with it even more insects to fight and even more maps to do all of that fighting on, so if wish to extend your EDF campaign by a dozen hours or so, feel free to give it a try.
You can find Mission Pack 2: Extreme Battle on Steam for €12, though its currently €9,60 due to its launch week discount. Have fun!