What formula do game developers use to make games appealing for gamers?

What formula do game developers use to make games appealing for gamers?

Bill Kunkel (Editor-in-Chief, "Tips & Tricks" Magazine) gives expert video advice on: What are the most influential first-person shooters?; What is one of the best strategy video games available?; What are some of the most influential role-playing video games? and more...

There's a thing that people pursue in game development for which there's not even a name; it's the fun factor. Sometimes you can have two or three games. Id you put them side by side and looked at them, you say "I don't see five degrees of difference on these three games". If you sat down and played them, one of them might just be one of the greatest games you've ever played in you life and the others might be so-so. It might be the interface, it might be the control system, but sometimes there are these elusive things; trying to nail down what it is that makes this game fun and this other game that seems exactly like it not so much fun. It's the most elusive thing to capture. It's hitting the G-spot in terms of gaming.