My 2yo son has loved this app since he was about 18 months. Besides it teaching him names for so many objects, letters, and numbers, it also helps his motor skills and figuring out which shapes fit different places. They keep adding additional puzzles when the app updates, it seems like there are close to 50 puzzles now. It's a great deal for a single app.
I also love this game because it doesn't have any links to the App Store, developer's website, etc.,, so my son doesn't mistakenly click out of the game, like he does with other websites.
I use a new BubCap home button cover too, so once we launch this app, I know he won't wander out. I heartily recommend Tozzle and BubCap home button covers, together they really help me share my iPhone with my toddler!