I seem to be running into a lot of bugs. The mobs will often stop at a spot along the path. This bug seems to happen when I build a dispenser nearby. I also have trouble scrolling the screen.
It would really help if there were a tutorial on how you can build paths. I found that sometimes I could paths catacorner from another, and sometimes I couldn't. I have no clue why. I also found that I couldn't put water on a bridge...a little too late.
But I really like the concept of the game, and the story is pretty awesome, too. I think that with a few tweaks, this will be a top-notch game.