DragonVale is all about dragons letting you hatch new dragons, breed dragons to get different breeds and acquire seasonal dragons that only are available for a short period of time. You are given two dragons at the start and new dragons do cost in-game currency, which you can earn or purchase in-app.
As you hatch you more dragons, you can buy new habitats for them, expanding beyond the one island that you are granted at the beginning. DragonVale is filled with a variety items for your dragon. You can buy breeding caves to make new dragons, decorations to makes your island unique, add new islands to expand your habitat into a full-fledged park and acquire other structures like a mini coliseum to race your dragons.
Like Backflip's other titles, DragonVale is very well done. The pace is perfect -- fast enough to keep your interests, but not frantic and stress-inducing. The game builds up nicely, with colorful and fun art. There's a social aspect to the game that allows you to add friends via Facebook or GameCenter and send them in-game gifts. You can even share your Dragon parks and visit other random parks to see what other DragonVale players are building.
DragonVale is free in the iOS App Store. It is compatible with the iPhone and iPad. There are no ads, but the app does include in-app purchases.