What struck me most was the similarity in the UI to the original game, both in screen layout and the interface elements themselves. If it works well, stick with it, I suppose. The narration goes over different elements of gameplay, explaining what is going on during the match. Gameplay appears similar enough that existing SC players might be able to just jump right into it.
Since they announced development, Blizzard has released a lot of videos promoting StarCraft 2, but given very few people access to the game itself. I hope Blizzard produces demos or give actual release dates soon, as opposed to simply more videos.