Last, hardest ending require you to met some specific conditions: take all the sigils from world A, B and C and all the stars in the game. Unlock all messengers on three islands. Finish all levels with the stars and get nine gray sigil. If you already did it all, the code to unlock the sixth floor can be found in each of three levels with the stars. Starting with A level read all the numbers from the board on the beginning of the levels. Enter the three digit code in the computer on the first floor and unlock the last, sixth floor. Before the ending, you must solve the gray sigils puzzle to unlock the last door. When you will pass through the last portal, you will finish the game. Congratulations!