If you chose the Constrictor Harness come to Venus, it is likely that you will get stuck during "Enter The Oberkommando" on the 10th floor. The last part on Venus requires the use of one of the contraptions in the game. Battle Walker and Ram Shackles are very obvious, but if you only have the constrictor harness, it can get a bit confusing because the crouching solution is a bit off. The solution is to just crawl through the narrow spaces, either left or right from the breakable door. This can easily be missed due to the faulty crawling detection in this area. You have look a bit to the side in order to trigger the constrictor harness crawl. If you crouch and look straight ahead, you just walk against the wall.