If you do watch this replay and want to get something out of it, I would suggest focusing on how the allies had a 'moblie' defense.
They used scouting to determine where attacks would come from, and attempted to concentrate their forces in that area. This gave them a HUGE tactical advantage compared to not doing so. Infact, you'll see that when the axis finally do break through, it's because the allies failed to scout and determine where they would break through and thus were unable to prepare for it.
The map also played a part: there were very few actual avenues for advance.
We had to make several using the Tiger.