http://mingw.org/wiki/MixingCompilers

I am well aware of the listed problems. 
However none of them are applied in this case (that is why I am seeking help on the list).

I do not use static libraries, I just try to use DLL compiled by MinGW in MSVC application.
All exported functions are in plain C, with POD as arguments, with the same calling sequence, no mangling, no cross-boundary memory allocations nor exceptions.
No struct alignment problem either. It is pretty bare metal C hard-cored DLL. 

Do you see any particular problem?