1337HAX go to internet options > increase your cache size to allow room for more temporary internet files, or delete your cache if you cant give more room, the game does save :P
Meh. I only used steal money and science missions and had no trouble at all. Shame the developer spent so much time into the other 4 types of missions which are useless :P
I believe to open the challenges you simply have to read the messages in the tutorial. One of them says "try the challenges after you finish the tutorial" or something like that.
So I'm playing on hard, looks like the only way to win is just wait and save money and then send supersoldiers. There should be offensive-based-strategy, perhaps catapults you can siege them with.
You should be able to pick your deck for the challenges, that way its more of a challenge. For example for Challenge 16, its all about restarting until you have a +invulnerability and the card that makes enemy go insane. Then you have to get lucky enough for him to not have two attack cards while you hope to get something to give you +HP. Oh yeah, and he has to get the taint insanity, anything else doesnt even help you.
@timothy you must really suck if it takes you that long to level up.
honestly dude, i went in a straight line until i found the boss, and then pwned him. no backtracking. <3