At the last hackathon I went to I was sitting in the audience at the presentation at the end with one teammate while the other one was upstairs pounding away at last minute revisions. We were scheduled last but I still had to make excuses to the organizers.
He showed up with something that basically worked but I kept cool under pressure, made sure I didn't commit to anything until I was sure about it, and used good showmanship. We were all shocked when we won the 'player's choice' award. Mind you, it helped that he was experienced at writing platformers in Unity and the other student could draw, but thanks to my showmanship people saw everything that didn't worked and didn't notice the bugs and people were left with the impression that 'wow that looked like a polished game' whereas the main author said 'I don't think I'd want to play it' afterwards. My continuous push towards a 'minimum viable product' combined with their push to make something that looked polish really helped that showmanship work.