>when you do it on a phone the portability and something about the form factor and touch interface seems to supercharge it

I recall reading something a while back (maybe even by someone at Rovio) that the simple finger motions across the small screen that were then novel to Angry Birds and the other early mobile touch games had some unique effect on the brain that other interfaces don't. The game mechanics are similar to those in Flash/Shockwave games going back to the 90s, but they become a lot more compelling on a small touchscreen compared to a mouse.