Thanks for the comments. FYI, SkyTroller was built to teach the basic skills of ATC and to give people a feel for what the job is really like within the confined spaces and capability of the iPhone or iPod touch. Since there was already a game out there that relied entirely on vectoring around an airport, we thought it would be fun to offer another view of the sport.
Altitude is called `the controller`s friend`for good reason. It is the primary tool by which separation is effected, with vectoring (changing direction) and speed control used very sparingly, especially in enroute applications. Terminal and airport control, not so much.
We`re already taking suggestions and dreaming up how we can add more features in the future. In the meantime, *IF* you can solve the puzzle using altitude separation alone, the FAA wants to hear from you!