Out of boredom, lets think of the worst possible bonuses you can unlock on the Poro King mode.
Just name some absurdly stupid thing they could have done to unlock an icon in this mode, but didn't. For reasons being there would be no working computers left in the world out of frustration when going for it.
"Poro Perfection" Win a game of Legend of the Poro King without letting the enemy team summon the Poro King a single time. (Reference to the perfect ascension icon that so many raged over trying to get)