The competition is for 11-20 year old football talents, not for professionals. It's a "vacation" you win, not to perform. Just relax in the swedish summer! if you are a superskilled guy/girl see it as a way to show your skills to others and to experience Gothenburg and the Gothia Cup tournament in Sweden.
Famous soccer players who have played in Gothia Cup as teens are: Xabi Alonso (Liverpool FC) from Spain, Andrea Pirlo (A.C. Milan) and Cristian Zaccardo (VfL Wolfsburg) from Italy, Emmanuel Adebayor (Arsenal) from Togo, Kieron Dyer (West Ham United) from England, and Julio Baptista (Real Madrid) from Brazil.
Good Luck!