Kevin Crawford uses the Open Gaming License so that the Ability Scores of Strength, Intelligence, Wisdom, Dexterity, Constitution and Charisma are used to make a character and that a D20 is used for skill checks and combat rolls.

But he uses these familiar mechanics in a very flexible and open horror role-playing game that lets the GM create a world out of well researched random tables. This game not take the now Public Domain literature of Lovecraft as the shorthand for the supernatural. Instead it draws from many different Pulp and Sci-Fi sources so that you the GM can build your own mythos from the common tropes of their practitoners in a mix and match fashion.

I would recommend this its own game or for use with other horror RPGs to flesh out adventures from the tables within.