TR: Guitar Hero--a game that lets people make music with a toy guitar, scoring them on performance--does seem instantly accessible that way. But it wasn't the first to use a toy guitar. What did you do differently?

EE: It's all about how you implement it, and it's all about the details of getting it right. If you look at Guitar Hero, there were so many elements of that game that took real rock music and rock culture and the sort of self-mockery aspect that you see there, and tied it all together in this humorous and satisfying way. But if you dive into some of the details there are some concrete examples of how it's better. We added a whammy bar. We knew we had to have a whammy bar even before we knew how we would incorporate it into the game. We had the five buttons and the strum bar. There's something particularly good about having five buttons, because you only have four fingers that you can use. So automatically, it introduces the notion of shifting.

TR: And it gives you the feeling, too, that you're doing something that you've seen guitarists doing.

EE: Playing power chords. We actually specifically authored chords that have this kind of pattern in them, so it really feels like you're playing a power chord.

TR: You founded Harmonix in 1995, Guitar Hero came out in 2005, and this hit led to the company being bought by MTV. What did your investors do during the time you were struggling to find a product?

EE: [They were] seriously patient. Most of them had forgotten about us and written it off.

TR: Then you showed up with the money.

EE: "Oh, by the way, here's a whole ton of money." Yeah. That was a really great moment, hearing from all those investors.

TR: What's next for you? You've got a formula that's really working.

EE: MIT really instills in you the notion of wanting to do original work, and not being satisfied by copying what someone else has done, and building new things. I think it's been sewn into the fabric of the company that being creative and original and innovative is just the way to do things. It's just kind of second nature. You look at the products that we've made, and we're always trying to do new things in new ways.

Harmonix is currently working on a game featuring the music of the Beatles.