To give a viablel idea you could use, you would need to consider the target audience. Primarily the target audience for Starcraft 2 is quite niche (ranging from 15 year olds to 28 year olds who are gamers).
What do 15-28 year old gamers want to see? "entertaining" games? what makes an entertaining game? the answer is fast paced action, innovation and good commentating. Maybe a small prize could be given out to whoever portrayed the most "entertaining" games throughout the tournament?
Such a thing would heavily encourage the players to succumb to the demands of the audience.
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I personally add in a bonus prize out of my own pocket for such games, it is rather meager (10$ for the winner, $5 for the loser). I do have high standards (game has to be good enough that i want to upload it to my youtube channel) thus i don't give it out very often but i have given out bonus prizes to players who played on stream and played fantastic matches. The main goal of me doing it though was to encourage players to want to play on stream and thus reduce downtime when casting seacraft events. So far i have awarded the bonus prize it 4 times. We could do it for the most exciting match every week, but tbh, most of the time we get pretty "standard" play which albeit is good, is also unexceptional. i do plan on continuing to offer my bonus prize for SEACraft events but it will continue to be meager in size as i can't afford to put in any extra.
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