@ocramot Meat is the only food available, it can be found as loot or sold by merchants. Food shouldn't be too much of an issue unless you're spamming rest.
An (easier) way to win is to mass units in one spot and spam their ability to get to the other side. If you commit hard enough, you can defeat the enemy before their units have a chance to get to your side.
Alien campaign is incredibly difficult in later levels solely due to the stupidity of allied A.I. Levels essentially become a 1v4 match, which combined with modes like domination and ctf, makes levels much harder than they seem to be intended to be.
For the hard badge, I found it helpful to use SirVoltsworth's build with a Fire rate swapped for an Ammo capacity, as the extra shots helped in the later waves, where you tend to get swarmed from all directions in the first few seconds.
I don't get how you're every supposed to get to space consistently in 5 days or less. In 4 days straight I averaged less than $10 per day, it's completely luck based.
 "Incremental Cubes")
 "Medieval Cop - Adam and Eva")
 "Rogue Fable III")
 "Pixelo")
 "Bit Battles")
 "Raze 2")
 "Reaper of the Undead")
 "Hedgehog Launch")
 "Papa's Taco Mia!")
 "BackDoor- Door 1")
 "Contract Wars")
 "Dawn of the Dragons")