This secret is looking like a trap but there's actually an hidden switch to escape it! You should see something if you zoom a lot on the automap.

For the file in Penumbra I agree it's pretty camoflaged, There's a picture where you should find it right here:

I figured you had enough answers and just left the thread ahahahah 
Sorry to hear your computer was broke ... And really no problems i was happy to help you out!!
For the sequel i'm trying my best on doing something greater. And i'm not that alone anymore on this one too so that's very helping a lot. I have a friend who do a complete original soundtrack for it, another friend who help me with the story and the dialogues, and another friend who is helping me out with programming. I wish on succeeding doing a sequel that will surpass the original in all way, and i hope people will love it as much as the first game.

A monster was placed over that picture? Damn i'm sorry about this -_- !!