I think you can patent just about anything you want to. The question is whether it will hold up in court or not. Most likely the example of the video game would not.

I worked for a company that had a very specific way of doing something that was far superior to anything else in the industry. No one else was willing to try it because they didn't want to risk something new. My company was able to sell systems at 1/5th the price because of our technique, which we patented. Once others in the industry saw it working, however, they decided to jump on board. Because we were a small startup we didn't have the cash-flow that they did and they effectively ran us out of the market. Now my previous boss (Because he had to let go of all the developers) is doing the only thing he can: suing for copyright infringement, because they are very obviously doing exactly what we were in the same way. They wouldn't do a thing until we proved it was possible, now they're going to run with it. I think in this case the purpose of the patent was to reward the little guy for being inventive and competitive. Of course, we'll have to see what the courts, and that is probably mostly dependent on who can afford the best lawyers.