Really good considering it was included with the game. The missions started getting really good towards the end, not so much at the beginning. The cutscenes were awesome, some good characters too.
I had fun playing it, I would say there is an URGENT need to vary the objectives though. Far too much powering stuff on and activating doors!
I rarely felt much connection between playing the missions and the story though. Also Sarah Palmer is just a boring predictable ball-breaker stereotype, every line of hers irked me. They were right to focus on Thorne as he is likeable.