Super Saiyan is one of the characters with two separate appearances. His first appearance includes straight black hair, white skin and black eyes. He looks like a little boy. He has a round face, fair skin, small nose and looks happy.
His second appearance shows when he activates his Power Button and sticks around after the Power Shot is activated. Clicking on the Power Button will cause him to lose any Costume he was wearing. His new form is defined by his spiky yellow hair, however, his expression seems to be much angrier. He still has fair skin, but his eyes are green and his mouth is gnashing. On his forehead you can see cruciform popping veins, which is a symbol for anger or irritation in Anime. It is thought that Super Saiyan resembles multiple characters from the show Dragon Ball Z: Goku, Gohan, Vegeta and possible some other too.
Super Saiyan's Power Shot is the Super Ball Shot. It is very similar to Italy's Power Shot, except that the ball starts in the air and it's blue. When the power starts up, Super Saiyan grows a giant ball of blue energy above his head. Then the ball shoots downwards towards the goal like Brazil's Firebird Shot. Whilst the ball comes down, it shrinks a bit to the same size as Italy's, and it will also lose its blue glow. The ball can hardly be deflected as it is a larger size, but can be countered easily like Italy's.
If you want to unlock Super Saiyan, the best way is gathering points to buy him by playing Head Cups. This is a much faster (and possibly easier) way to get him than playing 30 Tournaments with 26 Characters, which is very time-consuming as you have to win a total of 780 Tournaments.
Super Saiyan is a reference to an Anime character named Goku (and possibly some other characters too) in the Manga Dragon Ball Z.
He is the first character that, when his Power Button Effect is activated, gets blond hair. The others are Hong Kong, Ukraine, Serbia and Norway.
He is the only character that keeps his Power Button Effect appearance even after his Power Shot. He keeps that appearance until a goal is scored or the when the match ends.
His Unlock Requirement isn't necessarily the hardest, but it is one that takes a lot of time to fulfill. It takes more than 2,340 minutes to get Super Saiyan. That is 39 hours. And that is 1 day and 15 hours to get Super Saiyan. You have to win a total of 780 Tournaments, and at least 2,340 matches. However, Finland has an unlock requirement that takes even longer!