A new patch was just released by Eidos Montreal for Dues Ex: Human Revolution.

This latest patch addresses:
A frequent issue for AMD/ATI hardware users that can cause the game to crash on startup.
Improvements to loading speed. The speed increase depends on machine spec and settings, but loading time improvements of over 50% have been measured on some machines.
Some control fixes:
Diagonal movement is no longer faster as intended.
Adjustments have been made to mouse sensitivity in response to user feedback.
Mouse sensitivity for X and Y axis can still be configured separately, but is now consistent when set to default settings.
The range of settings for mouse sensitivity has been adjusted to provide for more accurate adjusting.
The default mouse sensitivity has been altered to be somewhat less sensitive.

Hope this fixes your game if you’ve experience any of these problems.