It was amazing, of course, but the drill itself makes me wonder. So my questions are:
1) How long do you suppose it would take to build something like that in real life? Is it even possible to make a machine like that?
2) How was the drill even built?
3) Where would you hide it?
4) Why would the general take so long to try to take it out? With the speed that thing moves at, it would have to be moving for several days.