I've known about this for a while and Zakblood is wrong - the CD Key works with the site versions.
And rather than merely being a convenience, it opens a serious vulnerability in their copy protection!
The CD-Key provided by Steam will activate Northern Inferno setup files available from Matrix (their ftp server and other sources)... CommandMANO-CommandNI-SetupRelease-v110.exe, and these can be patched right up to the latest beta build.
Why is this bad?
Because Steam has a refund policy. Thus, you can copy the key, refund on steam, and still keep the game by switching over to the Matrix version (which installs everything required for CMANO, COW and NI).
And, it gets far far worse...
I won't say how, but because the setup files that are freely available contain everything for CMANO, it is possible to activate the main game and COW DLC after this process.
A bit of guesswork would be required from someone who hasn't done it before, but its well known Matrix installations have a vulnerability in the way they check for valid CD keys. The upshot is you can get CMANO and all DLC for free from Steam and Matrix.
< Message edited by jaimewolf2980 -- 6/28/2017 11:55:45 AM >