10,000 Kleos:
To receive 10,000 Kleos, pause the game and press Down, Left, Down, Left, Up, Left. Note: This code can only be used once.
Infinite Kleos:
To get infinite Kleos, at the main menu, press Up(2), Down(2), Left, Right.
Defeating Giant Immortals:
To easily defeat Giant Immortals, use a spear to break their armor first, then attack them with whatever weapon desired. The gray bar is their armor amount. When fighting the second Giant Immortal, he will run away and start to regain health. Go to the statue he is beside, then push it on top of him to eventually defeat him.