Blender is a free, open source 3D animation, modeling and game creation package. It comes with an existing game engine called the 'Blender Game Engine'. Game design and programming sounds very tough to most people which is why not many people are into this field. It is the creative use of the right tools in the right manner that holds the key to successful game design.

So, what do we require?

Designing a 3D game requires the use of basically 4 things:

1. A 3D animation and modeling package
2. A game engine
3. A scripting language supported by the game engine
4. Other accessories like image manipulation applications for editing textures and sound editing packages.

Summarizing the whole game development process

Note that this process assumes that you have a ready-made game engine to use in your game.

The first stage consists of planning the theme (story) in detail of the game. After this phase, you will need to build detailed plans of levels and characters of the game.