The basic game here is collecting. NimbleBit's Ian Marsh has said that people really enjoyed collecting all of the various frog skins in DizzyPad, so that's the focus in Pocket Frogs. You collect and breed frogs of different types and colors, mixing genetic traits from parents to create new varieties. Frogs are placed in various habitats, one of which is called a nursery, where tadpoles hatch and grow into their hoppy counterparts. Breeding frogs together gives you new types and colors, and the goal of the game is to find as many as possible, earning experience and leveling up as you do so.
But what makes Pocket Frogs different from other games of this kind is that, at any time, you can take frogs off to the "pond," where there (are you listening, Ngmoco?) is actually a game to play. It's not an overly complicated game; the graphics are all borrowed from DizzyPad, and you simply touch to jump whichever frog you've chosen from lily pad to lily pad, nabbing dragonflies out of the air as you go. But even in this simple form (and I hope that NimbleBit adds complexity to the game in updates), it's fun! To tame a frog, you need to chase and catch a certain number of dragonflies, and as you're hopping around the pond, you can find other frogs to breed with and random gifts (which give you money, extra backgrounds for your habitats, or even brand new frogs). The pond gameplay provides a nice hook. I looked forward to the times when I had to go tame a new frog, and it was exciting to wander along and find a new gift to open up.
Outside of the pond, you can sell off frogs for money and use that money to upgrade your habitats, buy new types of frogs, or breed frogs together. You can also mail and send off frogs to friends, allowing for the Pokemon-style thrill of collecting and trading your favorite types. The "freemium" element comes in two forms: you can buy (with real money) "potions," that will allow you to instantly grow your frogs to maturity without waiting for the usual real-time period, or you can buy "stamps," which allow you to receive mail (including found gifts) instantly. Neither one is required, and you can actually earn both types of items in the game. If you want to stockpile them, though, you'll have to spend a real buck or two.
If there's a glaring miss on Pocket Frogs, it's a lack of Game Center integration. Ngmoco's Plus is integrated well (and it's a nice bonus that all of my freemium-loving We Rule friends will carry right over with me), but I would think that after the release of 4.1, Game Center integration would be a necessity on a polished title like this. It's a shame to earn achievements and not have them count towards Apple's score.
And again, while the pond game is a nice foundation for the social and leveling features, I'd like to see it expanded even further. You can go into the pond to eat more flies and make your older frogs "happy" (which raises their sale price), but for the most part, frogs are disposable. Once you catalog them, you can buy them back any time, so there's no real reason to keep them around. I'd like to see them have multiple levels of maturity and rewards for each, giving me more reasons to keep them around longer and keep taking them back into the pond to level up. And let's be honest -- I liked some of my frogs more than others, and there's no real way yet (like naming) to show off my favorites.
It remains to be seen if Pocket Frogs will take off with a huge audience. NimbleBit is experimenting here, and it's possible that they'll land somewhere in the middle of what they're aiming at, mixing genres in a way that doesn't make either audience happy. Plus, the potions and stamps are so apparently unnecessary that I'm not sure NimbleBit will make money (then again, I never use mojo in We Rule, and Ngmoco hasn't had too many issues with selling that). But even without other players, I've really enjoyed Pocket Frogs. It successfully combines the growing freemium genre with something besides growing crops and animals. The game will be out on Wednesday of this week, and it's definitely worth checking out.