Roxie, on lvl 19, remember that you have two cuts. Use them to cut off as much from the wood block as you possibly can without hitting the joint. I don't know why you shouldn't hit the joint, but that worked for me. You want as much wood off as fast as possible, so make it steep.
John1515, you have to go all the way through the science tree to the lvl 6 science: the destroy the earth mission. Once you've stolen it, then just plot it and execute it, fending off constant waves of attackers while it is executing for 3 minutes. Not very hard, though, with flamethrowers and repeater turrets on the moon base.
Would love a sequal
What do you mean? The shooting is awesome. It just fires a bullet and you're assured that it will definitely arrive somewhere sometime, if you're lucky.