Safari 3.1.1 (5525.20) shows colliding galaxies well. (running under Rosetta.) WebKit-SVN-r34710 shows nothing. r34655 failed the same way. I don't know what 'version' is. The choices provided there match nothing shown under 'about Safari' nor info as supplied by Finder.
Perhaps I was unclear in initial report: Safari running under Rosetta shows correct movie. Firefox 2.0.0.14 also shows correct movie. Webkit running native x86 shows nothing. Thus the subject line of this report was wrong.
The movie is displayed correctly by QuickTime and the QuickTime plug-in, but not as a stand-along media document (or in a <video> element).
This works well in SVN-r36120.