In the post-Matrix era, it's very easy to take the special effects for granted, but this movie is awesome and showcases the wonderful talent of Michael Keaton. He shows an EXTREME range, in that all the iterations of "Doug" are COMPLETELY different. They realistically seem like completely different people. Just watch the movie again and imagine a different actors face on each "Doug", which is not very hard because each one DOES have completely different expressions, mannerisms, etc. (i.e "Number 1"'s look of surprise when something unexpected happens is not the same as any of the others look of surprise) Summary: I believe most of the appeal of this movie is Michael Keaton's performance. You would expect that since he plays 4 characters, it would be kind of cheesy because they would be too similar and would just seem goofy. It's not. It's like 4 totally separate actors who happen to have Michael Keaton's face.