There was demo... 2011 based on different graphic engine and it looks completely different from the final version. I think gaming industry is still in wildwest where there are no laws. Devs should be taken to court for their marketing lies just like for any other deceivefull  business. 

Probably you have not played Dead Space 1 if you feel that DS3 feels scary. 

Dead Space 1 - Horror survival with action adventure shooter's elements.

Dead Space 2 - Action adventure survival with horror and shooter's elements.

Dead Space 3 - Action adventure shooter with survival and horror reference.