I completed a tutorial in about 30 minutes, meandering through a residential neighborhood. I hunted and pecked at unfamiliar commands, and enjoyed the robotic beeps and boops that accompany most actions in the game. The game seems to require that you have the phone open and unlocked while walking around to gather XM, so the best option seemed to be holding it in a roomy coat pocket, hearing periodic notification noises as I snapped up resources.
Playing Ingress, particularly when you don't really know what you're doing, has an element of social awkwardness about it -- I felt a little like a tourist in my own neighborhood, walking toward uncertain destinations, constantly glancing at my phone. Still, the speed at which Ingress will have you learning new ways around even the most familiar of areas is startling, and highlights how immersive the game is.
The technology, however, is still fairly embryonic, a fact clearly demonstrated by the frequent glitches I experienced when playing Ingress. While I admit that my aging phone is probably not the ideal platform for the game, it was still quite frustrating for it to continually plot my location as much as half a mile away from where I actually was.
The game wouldn't let me interact with a portal placed at a statue of Dante Alighieri, insisting that I was somewhere over by Kendall Square Station despite the fact that I was leaning against Mr. Alighieri's stony plinth, and placed me several streets away from a big cluster of hostile portals that I was actually standing squarely in the midst of. It was made all the more frustrating by the news, relayed to me by the game's messaging feature, that some clever Enlightened agent had nuked a huge series of friendly portals across the river in Boston while I fiddled and diddled. Not that I could've done anything about it anyway, but still.
It's important, of course, to recognize that Ingress is very much a work in progress -- currently, it's only available via invite to a private beta, though "#IngressInvites" trends regularly on Google Plus.
What's more, many have noted that the true purpose of Ingress may not be to provide a fun gaming experience at all, but rather to act as a source of pedestrian geolocation data that Google can monetize in some way. Time, obviously, will tell.