AquaForest is one of the more unique apps that you can get for your iPhone. It would be unfair to call AquaForest a game as more than anything else it's a fully functioning physics engine. There are game elements to AquaForest, such as the five different puzzle modes with ten levels each. These come across more as tutorials than actual puzzles as they teach you how to handle the free play mode.
Free play mode allows you to use all the different aspects of the physics engine and the different environments that you come across in the puzzle mode. The building options are borderline Photoshop style as they offer tons of customization with a multitude of tools. You can actually select several different ways to utilize each element or substance, which allows you a lot of different ways to actually set up your own environment.
The issues with this app are minimal. First, it does cost $7.99 to purchase it with no demo app available. One of the reviewers on iTunes made a valid point about the cost, stating that in comparison to paying $60 for a console game, the $7.99 spent here is much more value per dollar.
Second, the app does suffer from lag issues when you get into the more intense aspects of the engine. Both of these can be overlooked and rightfuly so as this app provides plenty of amusement and is a big step in the right direction for iPhone apps.