You're right, C++ pretty much has no serious alternatives for games. And not just games, anything that involves computer graphics, physical simulation, computer vision or image processing.

Python is excellent if some good soul has already written a library that does exactly what you need (in C or C++, obviously). The combination of numpy+PyOpenGL+PyCUDA is great for certain kinds of research projects (I have written a volume renderer in it) but probably far from commercial usability.

Haskell has great potential, but the community is too small and too academic to produce the necessary libraries and tools (which is a lot of work with minimal scientific content). The key problem is the absence of an industrial-strength array facility - there are many kinds of arrays in Haskell, all somewhat clunky and incomplete.

D might be a contender, but last time I looked the tools seemed very basic and it did not even support 64-bit systems.