Not quite "all valid Python." Just to be clear: nimic is a strict, statically typed subset of Python. At this stage, the downside of having Nim as an intermediate step is not really a slower compilation, as Nim compiler is very fast, but more like: debugging executable, might involve line numbers of the intermediate Nim or C source code; the need to install Nim compiler for development; memory management (currently it is ORC/ARC or manual in Nim, no borrow checker yet)