From what I recall, the cameraman had to dive out of the way of a falling Dave Mac armed with lots of spiky things so they didn't actually have any footage of the fall after the first split second. Does indeed look rubbish.
As mentioned above this was shot as a reconstruction to illustrate the story MacLeod was telling. We needed someway of ending the sequence, so we came up with the idea of the CGI fall quickly cutting to the credits.
I agree it doesn't look very good.
It worked better in the full film: MacLeod's telling the story, we see him struggle, then we cut to the CGI, credits and then MacLeod explains what happened. We wanted the audience to think 'what just happened?'... and then we explain it in the credits. It doesn't work so well as a youtube clip, where folk just re-watch it to enjoy our low budget effects!
In reply to diff: To be fair the video is great up to that point, exciting, atmospheric and some great shots, and its good to see Dave Mc 'on the edge' so to speak. I just don't think the CGI bit doesn't do it justice, I'm sure it comes across better in the context of the full film sequence.
Glad I didn't watch the clip! The full version is one of the best pieces of climbing film I've ever seen. Utterly harrowing to watch. Many of us will have been in similar situations (at lesser grades) and know well the feeling of sketching up higher and higher into a worse and worse position!