First, step into the power chamber in the middle of the vault of ages. Since there is only a limited amount of time you have to use the harmonic powers, choose a faster character to do this. There is a yellow meter that will show you how much harmonic power time you have remaining. Go straight up or straight down to reach the generators. The downward path has a small maze in it. Go right instead of left. At the generator, Apocalypse will be waiting. You must beat him up before you can destroy the generator. Destroy the generator and repeat the same process with the other one. It does not have a maze, and it will be a straight shot directly to it. Just like before, Apocalypse will be waiting for you at the generator. After destroying the power of the harmonic machine, he will bring statues of the horsemen to life. You must focus your attacks on the horsemen and get them out of the way before tackling Apocalypse. When you kill the horsemen, they will return to statue form. Then, kill Apocalypse twice to complete the game. Note: Make sure you have a full load of health and energy packs before attempting this.