Just downloaded this short demo from Xbox Live. I think it looks ace, the new 'mark & execute' feature is a welcome addition and the whole thing looks a lot grittier. Another new thing to Conviction is the 'last known position' where when you are detected, an outline of yourself appears. You can move into the shadows and flank the enemy while they aim at the outline. As I said above, its fairly short but you can take out a decent amount of enemies. If you haven't downloaded it yet, I recommend you do.