I've only been to one hackathon (Angelhack NYC), but I've heard that other ones have a similar problem - short demos. If you are evaluating a project in 2 minutes, you aren't evaluating anything except a team's ability to pitch. Granted, pitching is a useful skill, but maybe it should be called a Pitchathon because those of us who code all night get resentful of well-rested biz devs with a slide deck being in a 'hackathon'.

I know judging time tends to get limited, but one easy solution would have been to either split the judges up or use staff/volunteers to have some sort of preliminary round where you get 10-15 minutes to do a full working demo that shows all your work, not just a concept. The second added benefit is then you have a shorter 'final round' where only the best projects get demoed for everyone. The only downside is that not everyone gets to do a 'real demo' in front of the judges but maybe it's a good thing if it needs to be earned. I personally would have felt much better getting knocked out in an early round after actually showing all the work I put in rather than feeling like 90% of my work was irrelevant as far as the demo went because I didn't have time to show it.