5ever, or until 2024
You pretty much have what makes it a great module: 1) the humanoid horde and its mountain giant leader and 2) the strange hidden parts of the temple. Each are well done and stand out, both at the time and actually now. In our case, the players could not just take the horde out right away, even with a huge battle, and so there was a period when they would infiltrate one way or another, explore some tomb stuff, and then get out. This made the final defeat of the giant and co all the more satisfying.