Your sig says MICROSOFT = FAIL but you created a game just for Windows. I suggest one of these:
1. Use
Irrlicht or
OGRE. These are rendering engines, not complete game engines, so you'll need to choose your own library for physics, networking, sound, etc. This may be too difficult depending on your programming experience, since you'll be using C++ and not some scripting language. There are wrappers for other languages available, though.
1. Program in Python using Pygame and PyOpenGL. Python's an easy language.
3. Make a mod of an existing cross-platform game, such as Unreal Tournament 3.
4. Use DarkPlaces, a heavily-improved Quake 1 engine. If you want to see what this engine is capable of looking like, check out
Nexuiz. Being based on Quake 1, the engine is written in C, but for your game itself you can use the QuakeC scripting language. There are QuakeC tutorials at
Inside3D, along with a forum where you can ask questions. You can probably find some other helpful sites with QuakeC tutorials using Google.