Well after many months of waiting, it finally dropped through the letterbox yesterday and a little over 24hours later I've finished it.

Ok, so it carries on from where Tier 1 left off, but leaving aside the story and new features for those who have yet to play it, even running through on Easy, I found it ridiculously hard.
On top of that was the rather annoyingly heavy cinematics and comparatively slow response to the mouse. I'm not running it on anything ancient, but granted my quad-core isn't the very latest gaming machinem but even so, the one criticism I'd put over everything else it that this does lack playability