The complex was like a cross between Lost, Myst, and Cube. Every so often, alarm bells would ring, and all the inhabitants would be assigned random "jobs" they had to accomplish before the "shift" was over, or unspecified bad things would occur. So of course, when said alarm bells rang over the course of my introduction to the place, everyone swore and ran off, leaving me alone, wondering what I was supposed to be doing. One monitor screen labeled "Hints" said only "You can't see". Another said "Power", and from that I remember the room dubbed "the Power Station", a fairly dark place full of metal framework (double-helices, with one helix curved, the other with straight lines and corners) and several connected dials that had to be adjusted to match eachother's number.
Of course, being unfamiliar with the place, I couldn't remember how to get there, and by the time I found it (navigating an annoying canal puzzle in the process) I had lost significant time. I began working diligently, until I happened to look up and realize that the ceiling in this room was significantly higher than it was in the other rooms, and that I could use this to escape. Of course, I wasted no time, and got the hell out of there.
The complex, it turned out, was inside of another larger complex (adding eXistenZ to the list of inspirations). I quickly recognized the pattern and searched for another room with a hole in the roof or high up on the walls, climbing upwards and outwards. Things began to get strange. One room had a paper-mache cow followed by a paper-mache cow skeleton followed by a large empty pot. Another had vampires in strange green armor who only moved when you looked at them with the corner of your eye. I ignored everything and focused on escaping, until I came to the final level.
I assumed it was the final level, anyway, because when I parted the thatch walls with my hands, and peered outside, I saw only endless darkness. It looked almost exactly like what you see when you close your eyes after looking at a bright light and put your fists against your eyelids: darkness, but full of suggestive shapes: a series of abstract geometric patterns, a skull blossoming with flower petals, stranger things. I stepped back, unnerved despite (or perhaps because) of my realization that shapes only existed in my mind as a reaction to the infinite emptiness beyond. A traveling companion I picked up along the way asked me what I had seen, and I managed to get out "everything and nothing" before fully lapsing into an Obligatory Lovecraftian Protagonist Moment and laughing maniacally.
Eventually, I came to, realized that I had nowhere else to go, so went back, downwards and inwards. I reached the first complex again, in much less time than I had taken on the way out, said hello again to everybody, and got back to work.
And then I woke up.