Secret Room
On Level 4 there is a room where David and the zombies in the room appear to have doubles This is apparently the reflection off of a giant mirror After you kill the zombies jump up on a box in the center and push against the mirror You will enter a secret room that contains a pendant
The Sextant
On B2 while on your way to the yellow orb youll come across a room with some rock columns and a corpse with a scroll piece next to it In the next room will be 2 goblins and a floor button Instead of going there straight away stay in the room with the corpse and move over to the 2 columns attached to each other in the right corner of the room Attacking the columns will reveal that these 2 are actually made of ice and will shatter Behind is a switch that will open a secret passage to a room where you can pick up a device called Sextant