Some interesting observations...

[Zoma]

All weapons use the same ammo. This was done to simplify the game.

The interface has been vastly simplified. This was because too many gamers complained that the first Deus Ex wasn't consolish enough.

You don't reload weapons. This was added for realism.

Headshots don't kill people anymore. This is because shooting people in the head is BAD and the dev team didn't want to send that message to the kids.

The areas are much smaller. This is because some fans of the original were agoraphobic, and the Ion Storm team caters to the fans.

The skill system was removed, because RPG elements don't belong in an FPS and there were too many complaints about it in the first game.

The game is runs poorly on fast machines because the dev team wanted to create an gaming experience that would be equal to all players, regardless of their computer.

There is no quick save/load because the dev team wanted the player to be able to savor the experience of saving and loading.

Mouselag is turned on because it adds framerate to the game (note: I'm not sure what that means).