pygame in Debian testing is currently python2 only, I am sure I am not alone in thinking this is not a good state of affairs given that pygame is frequently used for introducing people to programming.
pygame in sid has python3 support but is held back from migrating to testing by three rc bugs. None of which have had any response from the maintainer. One of those is a FTBFS with python 3.7 which is apparently fixed upstream. So presumably the best thing to do about this one would be to update the package to the new upstream. I may have a go at this myself but I'm not an expert in python packaging so I don't know how well I will do. The other two are testsuite failures on architectures where frankly I doubt pygame has many users*. I may also take a look at these after the new upstream version is dealt with but I don't think it's worth putting huge amounts of effort into pygame on architectures where I doubt it has any users and I equally don't think it should be allowed to block the availability of python3-pygame in testing on architectures people do actually care about, so if the root cause cannot be found quickly I would propose either disabling the tests on these architectures or requesting the ftpmasters remove the binaries. Anyone have any comments or suggestions? *Both are very expensive architectures driven by IBM.