Here is a little tutorial for replacing the demo at the beginning of Redneck:
 
start the game with the command line parameter /r
for Rides Again this would be ra /r
also add the switches /v# and /l##
 
thus we have ra /r /v# /l##
 
the game will start and play to your hearts content just don't let the level end
while recordeing a demo or it won't work
 
the /v# switch picks the episode
the /l## switch picks the episode and map
 
give it a try
 
next time you play the game your demo will replace the scenes normally seen 
when you start the game
 
Speeed
 
2-17-00