Firstly, I'm a BC fanboy. I have every BC racer. (Just getting that out of the way).
I've spent just over an hour with the game.
First up single player, and initial impressions are that it's a little bit soulless and flat, but strangely I really found myself enjoying it regardless. Possibly the sensation of flatness comes from the slower cars when starting out. There seems to be plenty to do.
The single player structure is broken down into Challenger chapters, represented by a fictitious NPC challenger that you race against in a one on one at the end of the chapter, with multiple varying events in each chapter.
The races run like beta/demo but with NPC's. The AI seems pretty good. And yes, it seems that this game is not easy. From reading the Split Second thread, if people are expecting to blitz through the game coming easy first in every event, they're going to be disappointed. On my first run through the first chapter, I had to settle with 2 seconds and a third alongside the firsts in the other events.
So far there have also been destruction events (like on the beta/demo), and timed checkpoint challenges that feel a LOT like PGR, which is a good thing.
Strangely, the LA track reminded me of Burnout3.
Within each event, you also have the challenges of getting fans and/or picking up the 'in-event' gates challenge, on top of the primary objectives.
There are currently 2500 entries on the first single player event leaderboard.
So then I flipped over to Online, AND OMFG PUNCHING AIR WOOP WOOP!
This is so awesome. It's just as awesome as beta/demo, but NEW, AWESOME tracks.
Seemed like less lag too.
Love it. Fantastic.