Click the Replay button at the bottom right of the Login screen to view the list of available replay files. Select the file to be played back and click the OK button.
if you look at the log in screen, theres a replay button at the bottom of the list on the bottom right of the screen.
to make them playable in a media player you will have to use a video capture program like frapps or similar to make actual video.
the lineage movie capture can only replay with lineage, but its nice cause you can rotate the camera, zoom and such so you can get the perfect shots while recording and thers less lag then when ingame recording.