Beyond Blender Render/What You Need
So what do you need to make Blender Games? Here I shall explain:
Blender For Your OS edit
Number one: an OS (operating system). The best would be Linux, Windows, or MacOS. Next you should get Blender. Head to their site at www.blender.org and then look for the downloads page. Run down the page and find Blender for your OS. Download it and if you need to install, do so.
Next We Need GIMP edit
Not necessarily GIMP. Blender uses a system called UV Texturing. With this you can apply images to objects. To make these images you will need a reasonably good image editor such as GIMP. You can also download images from the web, but this may cause a run-in with licensing.
Other Stuff edit
You will need an idea. You can play around with tutorials and experiment but if you really want to release a good game you need to have a name, a game play idea and maybe even a story. If you're stumped at this you can use a quick version of mine.
A Good Imagination edit
You or someone on your team needs a good imagination. Using this you can imagine the landscape, gameplay, story, and menus of your game. Most importantly this can help with programming your game.