Space Ballistics
Space Ballistics is a mobile phone game. You need to specify angle and speed of the torpedo for hit enemy. Depending on sizes, planets pull the missile and make trajectory of this difficult.
To install the game, you just go with your mobile phone browser to ballistics.sf.net/get.
Otherwise you can download jar or jad files of the game and upload it to your phone.
Space Ballistics was created by the idea of Gravity Wars for Amiga computer.
The game was released by the free software license of GNU GPL, so you can download the source code and take part in the development.
The author will be glad, if you will send him your notes/ideas/patchs.