Apps for my nearly 4 year old

I'm still not sure about the wisdom of Reuben using my ipad as much as he does, not really natural is it? Continuum friendly? The Steiner people would not agree... but we have found some great educational apps and I like to sit with him. Here's our favourites:

Tallytots. Counting to 20 while doing cute things like racing little cars and feeding a chipmunk...

Shape-O ABCs. Really cute, shape puzzle and word forming.

Toddler Alphabet. More puzzles, words and the alphabet song, lovely graphics.

And then Reuben's choice of Dora the Explora and Peppa Pig apps...