Invisible War isn't a really successful release of Ion Storm, I don't know why - probably because a talented person whos name is Warren Spector didnt lead the project himself. Also, they've tryed to manage so the game works in X-Box or whatever, which is not good because they've downgraded the things you make manually in DX (hacking stuff and etc).
Invisible War is not a cyber punk game (actually DX2 is sci-fi), while DX1 is. It's another gay gossip made by "reviewers", who earn the money on their "reviews".
Invisible War is more fantastic. But it contains some kind of an unique atmosphere, but when you start playing it - you don't feel it.
Yes, its a very short game. As a tip, when you're walking throught it, try to complete all the avaible tasks... makes gameplay a bit longer and a bit more interesting.
It has good physics, but sorry, no good graphics. Graphics is good only because its dark..., while in UnrealTournament04, which has the "same" engine, the graphics is much and much better, and in Ut04 you're able to see day and daylight, while in DX2's engine, i think, its simply impossible to do (daylight requires more shadow/cloud processing)
A little story about engines: there was an Unreal engine (DX1 and UT99 is running on it), Epic games (a developer of the engine) has modified it a bit and called it "Unreal 2" engine, after that, Ion Storm (creators of DX1 and DX2) bought unfinished version. Epic games continued working on their version, to make UT03 and UT04 sooner, but Ion Storm tryed to continue engine's development by themselves. Unfortunately, Ion Storm coders weren't that good as Epic Games ones and thats why DX2, without patches, lags as hell, while UT04 lags less, and it may run ten times bigger maps.
About patches: when you, Bob, bought DX2, don't even try to start to play. Download latest patch 1.2 and install it. Download crack if something doesnt work (ask me for this). It will reduce major lags, and also fix the game bugs.
I disagree with AlexDenton about augs - i think, there ARE good augs, but we demand more

And also, what for did they shorten the skills system?