I've done three land battles since the Mauna Roa mission, and they were all ridiculously easy in comparison. Don't know why they made the first one so hard, but the rest are easy money.
The text quests are a lot of fun, too. They make you do all sorts of crazy stuff.
I've noticed, however, that there isn't a whole lot of information about this game available. The official forums are dead, there aren't any fansites, and even Gamefaqs doesn't have anything more than a collection of random tips that were copied from a thread on TotalGaming.net. I can't believe there isn't any community around such an awesome game.
Anyway, I'm working on a guide. Never done one before, but it sounds like fun.