All right, now I'm on the same page. The game indeed requires Microsoft Visual C++ 2008 runtime and OpenAL installed in the system, which requires admin rights elevation for installation.
Technically I guess you could avoid installing those by just obtaining and copying the dll's from the runtime and OpenAL to the appropriate Windows system folders, but in any case, you'd hit the admin rights issue that way too as you can't write in any of the system folders.
You might be able to achieve something by adding the required dll's in the game's folder and mucking around with the manifest files for the game AND for the runtime dll's, but I've personally never bothered to look there.
EDIT: This might be helpful:
http://social.msdn.microsoft.com/Forums ... vclanguage