Universal Plan B wrote:

Thief did sound, but SS2 took it to a different level. In Thief you used sound to navigate the game. In SS2 you did a bit of that, but the game also used sound against you as the main weapon to frighten you.

A psy ops can learn invisibility without too much hassle.

I'm pretty sure there are people who beat the game without killing any of the standard monsters. There are special dudes you have to kill like the end boss and the ninjas with keycards...

Degrading weapons is just irritating. I can't think of any game ever which would become funner/scarier if you caused the weapons to fall apart after 10 shots.

I don't think it was about scaryness primarily. It was more about forcing the player to make decisions. That's what SS2 did more than any other FPS before or since,

and the thing that has been copied the least.

Everything from the obvious decision of what RPG stat to increase to the subtle decision of weapon choices. That's one of the reasons that it was a deep game, besides the stuff like story and level design.

And yes, the game was a bit more tense when I was holding a pistol, knowing that I would have to retreat from anything big, because I needed to preserve my rifle.

So what's left? Message logs? I guess that must be it! The secret to making your FPS go deeper is message logs!

It was good enough for Doom3 to copy, wasn't it?

So I take it you're a fan of the Derek Smart games?

I said failing to reaching perfection. Derek Smart games fail to reach mediocrity.

Some other games with lots of great ideas but also some flaws that cause some people to hate them: Far Cry, Morrowind, I-War 2, GalCiv, The entire RTS genre