Don't piss me off
I was just finishing the part with the locked chest and the vent. Why not be less offensive to your viewers by not telling them they are cheating when they press tab to see if there is any other button they need to press in addition to the combination, because they are cycling through every possible combination and don't want to miss it? I eventually found a walkthrough back around page 15 or so (as of this posting) that told me the number was 831. If my intention were to cheat, I would just click play. Don't insult people.
Also, the whole point to opening the box was to get a screwdriver. Did the thought ever run through your mind that you HAVE A KEY ALL ALONG and a key WORKS ABOUT AS WELL AS A SCREWDRIVER when the bolt is flat on the wall? Or did that just slip your notice?
This does have good atmosphere, a compelling story. Except for the reasons above I would have liked to rate this 8 or 9.