During my college years, I won a bunch of hackathons. Maybe like 5 in a row. Hackathons fundamentally are all about how cool the demo is. Every time I've worked on a hackathon, I've come up with the demo first and then, worked backwards. I even remember an instance where a fellow summer intern asked me what I was doing that weekend. I said I was going to do a hackathon and win it. And I did.