Beat Puzzles 41-50.
Unlock the credits by either solving all 100 puzzles, or by completing Challenge mode.
Beat Puzzles 1-10.
Beat Puzzles 71-80.
Beat Puzzles 11-20.
Beat Puzzles 21-30.
Beat Puzzles 81-90.
Beat Puzzles 51-60.
Beat Puzzles 31-40.
Beat Puzzles 61-70.