Obtain Access to Facility Vent (Dam)
Ever had doubts that it would be practically impossible to enter access to the vent underneath the platform of the Dam? Well, I have found a way in which this is now possible. However, the instructions must be followed correctly or this might not work, it also may take a few times to get it correctly funtioning.
First and farmost, enter the codes (No-Clipping & Level Override) below and start the game. Additional in game codes can be used if desired. From then, enter the Dam level on any difficulty. When you have started, run all the way to the platform and follow these instructions theroughly.
Jump off the platform of the Dam. Keep in mind that you will not need to jump to the actual bottem or you will need to restart at the top again. Jump off a bit higher where the light comes up from this platform, so in fact, you will be hanging on the Dam above the platform right above the light. Then, press the L & R buttons to activate the No-Clipping code. You will then need to walk away from the Dam into the open area, from which you will fall. You will actually start falling past the platform and underneath the level. From then, look back up to the platform facing the Dam and start walking, which will cause you to float back up. However, it is best to walk slowly. You can then walk right inside the platform and see the vent. Although, this vent obviously leads to a dead end and is quite small in size. If you did not do a step correctly, try again untill you get it proper.

Special thanks to the Terrorist for these pictures.
Code created by Craig Stickland
Base Codes:
No-Clipping Codes:
D0064F31_0030
800D33F5_0050
Level Override:
80030980_00FF