What was the name again of that central Bar in a bunker, where all the Duty guys hang around ? You know what I mean, where you can trade items, and get a few assignments.
Well, the road leading to the front entrance of that bunker, always has some dogs running around, chasing you when you approach. There's a grassy area besides the road, and those dogs are always runnning around in circles there, whenever you show up. This meadow is bounded with a fence, but it clearly continues beyond that fence. I once noticed there was a small hill next to the fence, and by walking up that hill, it was possible to actually jump over the fence.
I found out soon enough that this was not what the developers had in mind. Elements of the landscaping were missing and the scene turned into just a barren plain. But surprisingly, when I continued through this landscape to further places that I knew for sure were "chartered territories", they too were incorrectly rendered. I assume that the scenery for these locations is only triggered when some well-known borders are crossed, not the "wrong" borderline over which I had come.
The whole game had turned into a half-completed landscape, with no game characters anymore. I tried to get back to normal by jumping back over the fence, but that wasn't possible as there was no convenient hill at the other side of the fence. I ended up falling into some kind of shallow pit, and from then on, roaming the no man's land half submerged into the soil. Eventually I fell even further, hundreds of feet to the "bottom of the world". Stuck.
This "falling through" is also a regularly occurring bug in the rarely played Project IGI. Being close to a door that is in the process of opening or closing, can force you out of the regular space, into the walls. You get to gaze around in the endless blue "behind the scenes", while some of the game scenery is still visible. Once in that void, any further step will then cause you to lose your foothold and fall a long way down, until the whole level layout is just a single dot high above.