I've been playing around with this for a bit.
As the Entente I did pretty well in the First Battle for Ypres holding the line and slowly pushing back well enough ahead of the historical situation. However, I didn't get a victory screen when the scenario was supposed to have finished. I could just keep on fighting into December.
It's a fun game with lots of little nuances to the core game that add to the immersive feel.
I've dropped an email to Bill Runacre (lead designer) on the victory screen thing and will let you know his thoughts on it.
I've since been playing the second battle and it has a very different feel to the first battle with poison gas, better trenches and better defensive combat values reflecting more emphasis on MG's in 1915 compared to 1914.
All in all I recommend it. It has some minor flaws, but on balance I like it as it seems to reflect technological and doctrine changes in what can be quite intense battles.