I was a fan of 'Mork and Mindy' and I forgot that the show went through all these problems. I just remembered what was good.
Chris Diamantopoulos imitated Robin Williams' comic style perfectly; I could easily imagine what it was like to see Williams himself doing all those crazy things. Whoever wrote Williams' funny lines did an excellent job, whether this included ad libbing or not. Still, at least early on I felt like all I could do was imagine it was Williams. I don't think anyone could truly master his style, though Diamantopoulos made a valiant effort. In one of the final scenes, Diamantopoulos did a very good job imitating Williams' co-workers.
When Williams was not funny, Diamantopoulos did not always show talent. But in a couple of scenes associated with an unusual episode of the show which was Williams' idea (not the network's), Diamantopoulos really shined as a dramatic performer, and really made me believe he was Williams. He also did well in a couple of instances where Williams criticized Mork's portrayal.
Other than Diamantopoulos, unfortunately, and except for the actors playing John Belushi (Tyler Labine was fantastic) and Raquel Welch, I didn't see any real acting ability among those playing celebrities. Though the actors playing Laverne (Stacy Fair) and The Fonz (David Josefberg) portrayed those characters better than they did the real-life actors. Daniel Roebuck especially needs to be singled out, because unless he was intended to be a parody of the genius director/producer Garry Marshall, he did not achieve what he was attempting. Marshall was not a moron, though Roebuck did the moron role very well on 'Matlock'. Later in the movie, though, Roebuck did come across nicely. And I loved the stunned looks on the faces of Marshall and Harvey after Williams auditioned for them.
Of those actors not playing celebrities, Michelle Harrison did the best job, as Williams' wife Val. David Richmond-Peck did a capable job as Harvey.
I enjoyed the scenes related to the show itself the most, though I couldn't help but think the show's live audience was doing a fine job of acting. Except for Diamantopoulos, I didn't think anyone was that funny. I was especially disappointed in the portrayal of Jonathan Winters.
Of course, the usual constant criticism by the network just had to be included, as it often is in movies like this. That was fun, though, especially when the censors were kept hopping by Williams' antics.
The scenes related to Williams' personal life were well done but not that pleasant, though not as bad as I expected. The scene where Williams met Belushi while doing his stand-up routine, and the one where they got to know each other afterward, were quite enjoyable.
Overall, I was fairly happy with this movie.
