jdsgn: You and some others mentioned Thief, this also is one of the highest rated games on GOG.
What makes it so special?
Great atmosphere, pretty good story, and back when it appeared, it was unlike most other games; there weren't many "sneaking & hiding games" back then; I think the first Thief appeared around the same time (late 1998) as e.g. Metal Gear Solid on Playstation, which was also kind of a sneaking game. I think both Thief and MGS were the reason why we started seeing more and more sneaking parts in other games too, e.g. No One Lives Forever etc.
That being said, I think at least the first Thief game is maybe a bit overrated, but still ok. Main things that bug me:
1. The map design in most levels is quite poor, almost nonsensical. It is as if the map designers just tried to make as maze-like maps as possible, with identical-looking corridors and places. It didn't help that the "paper map" you had with you wouldn't really help much navigating; then again having such a low-detail map that didn't show where you were was kinda realistic I suppose, but it was also pretty useless usually. You could just as well never look at the map, and just try to learn level by heart as you go.
More than once, I was totally lost in some of the levels, no idea if I was walking forwards and backwards, and no idea where to go next. In a couple of levels, I had to look some youtube gameplay videos just to get a hunch where I was supposed to go next, after hours of wandering in circles in the level.
2. Partly because of the above, most levels to me seemed to become:
- Sneak around in the level, trying to club down every guard and servant (or kill every zombie or burrick) you can find. At the same time, try to learn the vast maze-like level so that you can later actually navigate in it at all.
- After you have emptied the whole level and learned your way around a bit, now try to concentrate to your actual objectives.
After all, quite often the objectives were to find some well-hidden object in some farthest room, and gather enough loot, and doing those would be much harder if you had to worry about guards, civilians and monsters sneaking at your back. So just forget about your objectives, until you have emptied the level from any other living creatures.
It just made me make a big "sigh..." at the start of each level, not really feeling excited to explore a new level. For some reason exploring wasn't that much fun in Thief, it felt more like work. It probably had to do with the poor map design mostly. There wasn't much to look for, when exploring.