A very convenient shadow around where the nose would be stepped if the have one. Maybe they saw what McLaren had last year and it has takn them longer to launch as they redesigned from th ground up to avoid stepping the nose and just don't want to show it yet?
Also signs of an interesting ridge down the engine cover, very short and compact side pods, plus a very tight back end compared to normal, though tht may just be the way they have shown the lighting on the car....