I have no idea how fast your system is, but lag is very dependent of your system, my system is fast enough for it... I think it was one of the AUM's in which a pretty nice code for recorded cutscenes was, it did just about the same thing; take screenshots and name all the .bmp's accordingly (screen001,screen002,screen003, etc.) and loaded all those screens by c-script to playback the movie. It would be nicer to use all those screenshots to compile a real movie instead. Yes, sound would be a problem, but there are ways to record that too, but basically that would be the hardest to 'solve'...

Cheers