I think even as a stand-alone game, DE:IW is mediocre. The glowing testamonials and reviews really are suspect.
The developers hyped so much this idea of "in-game freedom", "multiple factions", "multiple choices", etc... but each time you go against a faction, they forgive you and give you one more chance. In short, there never is a feeling of consequence for your decisions, something I felt much of in the original Deus Ex. The side missions are seemingly pointless, and your only reward is cash, of which you never really need. You can nearly finish the game without installing *any* biomods, and I myself used no other weapon than my pistol. I had heaps of biomod cans and weapon upgrades, all unnecessary to complete the game.
Some of the design decisions were fairly thoughtless, and you can easily tell it had an X-box model from the ground up. Dialog text has huge fonts - great for sitting across the room while playing a console, but hurts the eyes when sitting 2 feet from your PC screen. There's no view-bob (more of a "floaty" movement engine). Small shoe-box levels with multiple load zones within each level (with PCs pushing 1gig RAM and more, there is no excuse for this). The PC version does not support surround sound or even EAX, though many previews were boasting of all the sound advancements DEIW was to achieve. In fact, the dialog is so compressed, it's hard to listen to at times.
Out of the box, the PC version is not very playable with the default control scheme. Mouse is extremely sensitive, mapped keys don't stay mapped, a muddy mess really. Speaking of the box, the screenies on the box are pre-release, hi-res, full bumpmapped textures, which do NOT appear in the final game... very misleading.
Dear lord I could go on and on. But if you *do* decide to purchase this game, there are 2 mods you should immediately download before even playing: 1) tweak mod, which fixes many of the control issues mentioned above, as well as the font size, etc... (I think the official DEIW patch 1.1 fixes some of these issues, but the tweak mod is much more comprehensive) 2) the community hi-resolution pack (basically a small modding group got together and re-textured over 300 of the original textures - looks MUCH better with this resolution upgrade). It's disheartening when two of the patches considered prerequesite to playing are created by the mod community and not the devs themselves...
Both of those can be found at the ion storm forums. If you do try to play the game out of the box on a PC, you will be very frustrated. I can't over-emphasize this...
OK, I'm stopping this rant because I'm getting off topic, sorry. Just frustrating to see what happened to DEIW, and to know the exact same thing is happening as we speak for the upcoming Thief: Deadly Shadows game.