1) http://d.pr/i/FOZk That very last line, システムメッ???? can't really parse this into anything that looks like a real word. What could this be?
2) あの時蹴る方向どうしてわかったんですか？ // ああ あいつ昔っからイザって時に出るクセがあんのよ オレの封印された左がどーこーよく言ってたからなー きっとそうだと思ってたね I don't really get what the character means by オレの封印された左がどーこーよく言ってたからなー The question was how she knew that the guy she's talking about would kick the ball to the left. That guy has an injury on the left side of his face that she caused a long time ago. Could that be related?
3) Referee command right before the fight ステイコーナー！！, is that "stay corner"? I don't think I've ever heard it.