Awesome way to learn programming basics!
My overall opinion of Lightbot is that it is a wonderful tool for introducing programming concepts. I like the way it guides the learner without being heavy handed or too obvious. The Hour of Code version (http://light-bot.com/hocflash.html) is shorter than the app, but it's free so I am not complaining. I actually bought the app for myself, and I'm struggling to complete all of the challenges. In my opinion this is for middle school and up. Younger students will struggle.
How I Use It
I used Lightbot with my Robotics classes to introduce them to programming robots. We used the online game not the app, but they are very similar. The program teaches students the basics, procedures and loops. It is a great way to learn programming concepts, and for us, a great way to practice programming robots before actually programming robots. Some students got frustrated when they got to the higher levels, but with some hints and careful questions they were able to move forward. Some students cheated and found the walk-throughs online so keep an eye on that.