Anyone whos likes Shadow Complex has got the game. The curious amoung those gamers has upon release, probably come across some snippet of information from IGN's Hil, who was shown a secret by the games developers Chair. After seeing it he said that anyone who was to attempt to find this secret would be crazy.
So... over on GameFAQ's the boards hottest topic was the 4% run achievement, a.k.a. 'The Insurgent' complete the game with 4% of items using only the grenades, foam and missles. Soon curiosity got the better of a handful of gamers and made it thier mission to find this apparent hidden secret. Over the course of what took a collective of people around three days. it was finally cracked by cooler.

It took only 20 minutes before I was able to replicate the requirements and saw the missle style gate close in front of me and I then determined decided to start over with a silent determination to reach this goal. and on the subsequent run filmed the results. (which is at the end of this post.)

Eventually it will probably mean the annhilation of the campaign time leaderboards....... Still let the insane world record times be logged and accounted for :) I wouldn't be suprised if someone found even more skippable areas getting times under 25 minutes. Still if like me you really enjoy Shadow Complex this secret will most likely extend your gameplay of this wonderful XBLA title. I know I still have to remind myself its a XBLA game and not a full retail release. So enjoy the vid and good luck with those attempted speedruns.

[EDIT] To clarify: The gap I falldown after surfacing from underwater, is the secret. If you dont reach that area fast enough the floor closes and it remains inaccessible for the rest of that run. Enough testing seems to show it closes after 5 minutes of a brand new game. But doesnt open until you defeat the 1st boss. So you have to get to the boss and back in under 5 minutes, or its closed. This secret enables a person to beat the game in 30-35 minutes.