I'm releasing the engine I developed over the last years (and that I now use for all my games), to the public. It is free for use for non-comercial projects, and there is a indie license that costs 100$ for those who want to release commercial games.
The best feature of it is that allows programmers to write the game code once, and in some minutes you can have your game running in lots of different platforms (iOS, Android, OSX, Mac, Linux and Windows).
It does not support Objective-C, but rather Object Pascal (
http://www.freepascal.org).
In some weeks I will release a update to allow using the engine with other programming languages (Javascript, PHP, Lua and C).
Here's the website with more information, and list of features:
TERRA Game Engine