Hangman in A Prisoner Seeking An Escape level:
When you reach the bottom of the chamber in the A Prisoner Seeking An Escape level, kill all the sand creatures and then enter the cell to the left when looking at the save point. In the left corner of the cell is a little joke on the wall. Take a closer look in first person view at the drawings you find there. Obviously the prisoners where playing hangman here.

Tomb doors puzzle:
Near the end of the game, you are in a tomb with infinite doors. You have to find the correct series of doors to progress. Go to the landscape view. Always start at the door with the face above it and go clockwise. The order is:

1. Fourth door from the entrance
2. Seventh door from the entrance
3. Third door from the entrance
After you have successfully done this you will be taken to the second level of this room. It is almost the same, just with more doors. The order is:

1. Fourth door from the entrance
2. Ninth door from the entrance
3. Fifth door from the entrance
An intermission sequence will then follow.

In the circular room you find in the tomb, there are doors that you must enter in the correct order, or be teleported back to the start. One way to make sure you go through the correct door is to listen carefully. When you are in front of the next door that you need to enter, you will hear the sound of trickling water. This indicates that you are standing in front of the correct door. Repeat this until you have solved the maze.