The C++ you end up with by following Google's style guide is more of a "C with classes" thing, they prohibit several central features of C++. That said, I understand that they mostly do this to be consistent with their older code bases. But it's not exactly a style guide I'd follow strictly in a new project/team.
c++ exceptions? in an unmanaged (runtime engine not managed by some sort of VM) language you can't really assume anything when an exception occurs, you can't assume that you will be able to allocate more memory from the heap, for instance - if the heap is corrupted then this will just not work.
RTTI ? it costs a lot, well and you can do without it; Besides requirement of RTTI (assuming that the library does RTTI) will prevent you from using third party libraries that might be of use. Resolution: skip.