Like LEGO Duplo World, this well designed subscription ($10/year) service lets your children play with Marvel characters like Spidey and Captain America in an open-ended, "save the world" format. You can fire spider webs, rescue a kitten and build with Marvel themed virtual bricks. Note that this app is free to play but additional paid content is offered, consiting of a subscription service that unlocks all current and future content. The subscription automatically renews