I'm. Addicted to this game. Easy way to pass my lunch breaks. The added level difficulty of the pId version is worth it.
I'm sorry to say, but robodefense sucks compared to almost all of the TD's I have on my ipod touch. The graphics are circa windows 95 and the gameplay is tedious and unimagined. Go play geodefense or Geodefense swarm (or look for vids of gameplay on youtube) and see what a real tower defense should play like.
I just bought this game and I'm having fun with it. Do you need to start with gun towers at first? I'm getting to the point my gun towers do almost no damage, but I don't have upgraded starting money to the point that I can build all rocket towers to start out with. So I guess I will need to use some upgrade points on guns? Just wanting to see what others have come up with.