Complex sentence: At the 2011 QuakeCon, Carmack mentioned that the new "Doom" would be using a new scripting language based on C++ and called it "super-script", a subset of C++ with features such as scheduling and type safety.
Split into simpler sentences: At the 2011 QuakeCon, Carmack mentioned that the new "Doom" would be using a new scripting language based upon C++ and called it "super-script". This so-called "super-script" is a subset of C++ with features such as scheduling and type safety.