This thing is addictive. Discovery Channel originally had this game developed to help market and drive traffic to its Future Weapons show.1 It was then ported over to the iPhone just a couple of days ago.
I myself downloaded it right before taking the bus home from work. I usually take a nap on the short-ride home but I just couldn’t put this down. I would definitely recommend this game as its free from the App Store. Here’s the direct link to the Cannon Challenge’s App Store product page.2
The only downside to the game was probably its easy learning curve (literally). I finished it in less than an hour…
I’ll see if I can post up some tip(s)/screenshots of my strategy and technique later =)