Hi Mark - You're completely right. It's not healthy to do anything for 80 hours + I would hate to sit through 80 hours of WoW :) Too much of anything can become a bad thing, and you're completely right that we need to make sure we don't burn ourselves out.
We, of course, hope that we will not have to work 80 hours every week down forever - but at an early stage we can't help ourselves. The extreme motivation, energy and drive in the team keeps us running.