Did most of the single-player campaigns. Bought me some weapons. Well, almost all available ones (unlockables, as crates, at least). Surprisingly, tutorial mode pays out, so don't miss out on that extra change when you have an opportunity.
So far, buying campaigns is the additional 5 missions on the side. And the concrete donkey, nasty weapon. It drills straight down with banana-bomb power per-impact. Un/Fortunately it's an airstrike weapon, so no go in caverns.
Oh, and one last note;
THE COMPUTER IS A CHEATING BASTARD!!! How the hell does it manage to pinpoint their shots? I mean, a precise blast from a grenade to get the mine to explode at just the right time to not only kill my worm(s), but also drown them. Other times, where it seems doubtful for even a human player to fit a shot through, computer has the accuracy of Luke launching a torpedo into the Death Star.
What the hell computer?
One recent dick move the computer also pulled was letting me abuse the infinite blowtorch and delayed time for one of the nearby worms (I had a good spot at the time). I kill that worm, only for his buddy to prod me into the drink thanks to running out of time before getting away from the edge (and also a barrel burning JUST enough space to wedge a guy through as well). I never felt so pissed off at an AI player. The computer prodded my only guy towards death. I never thought I would feel humiliated by my own machine.