This patch brings a pretty focussed single feature, which is that the game now pauses when the Steam Overlay is displayed.
Although this may seem like a small feature, it actually involved some quite involved work. Once the basics were in place, i.e. the pause when the Steam Overlay was displayed, it did show that a few of the features of the game did not actually pause correctly (this is an on-going task).
From this, a rabit hole opened up, and we had to visit a number of elements to ensure they paused as they should.
The end result is that the pause is now a little more robust. If your interested on WHY Pause has taken so much time to implement, have a read of my Blog post on the matter.