Unlock Skill Challenge Puzzles
Rookie - Get 30 stars.
Beginner - Get 40 stars.
Amateur - Get 70 stars.
Mania - Get 100 stars.
Veteran - Get 130 stars.
Semipro - Get 180 stars.
Pro - Get 230 stars.
Expert - Get 300 stars.
Specialist - Get 450 stars.
Sudoku Master - Get 650 stars.