How can I watch a partial WMV, partially downloaded in eMule?
I know it can be done for MPGs.
MPlayer can usually handle "broken" files.
There are various (newer even) third-party adaptations, front-ends around. http://www.mplayerhq.hu/design7/projects.html
The beginning of the file (at the least) needs to be somewhat complete. Otherwise, so long as the file is not locked (read lock), MPlayer can usually do something with it.
VLC can usually play partially complete or corrupted files, though it depends how complete the file actually is.