Q: Did you incorporate any ideas at least in part inspired by Invisible War? Or was it entirely ignored?
...the truth about Invisible War is that I personally did not get as much enjoyment out of it as I did the original Deus Ex.
Looking at Invisible War was a cautionary tale. The game showed us how some apparently simple design decisions such as universal ammo could alter the essence of what Deus Ex is. When you look at IW, all the staples are there: the future, augs, weapons, a conspiracy, dialogs, stealth, side quests, etc. Yet it doesn’t feel quite right. It made us realize that it would be very easy for us to screw up Human Revolution. We had a fine line to thread after all.
So in essence we used IW and compared it to DX1 in order to operate a “course correction”; which means we reverted most decisions in IW in favor of what DX1 had done. From my knowledge (and sometimes defective memory), there is nothing in Human Revolution that comes from invisible War alone.
Q: What idea for HR looked amazing on paper, but simply did not work in the game? and what was it that didn't work?
But there are so many!
Some dialogs were supposed to feature objects hidden in the background that you could find and analyze in order to unlock blackmail attacks that you could use to convince people to give you stuff. Unfortunately, you had to do this while the character was talking to you, so you had to concentrate on 2 things at once, which meant nobody was listening to what characters had to say.
The hacking was also supposed to be much more complicated than it is right now. Before accessing a device, you had to scan it for active ports. Some ports were slower but less protected, so you had to choose the best one for what you were attempting (whether you wanted to control or download something). Then you had to assign CPU cycles to various attack and defense programs while the system was trying to trace you. Anyway, we had it working in Excel and did three revisions before it was canned for the current node-centric system. People just didn’t get it.