It is beyond me why critics had such a problem with Errol Flynn. He was, even in his worst films, an excellent actor. I think people let his personal flaws and wild personal life cloud their opinion. I think Errol Flynn is one of the most under-rated actors in the history of film, and never got the respect he deserved. Yes, part of that is certainly his own fault, but definitely not all of it.
Mara Maru is unquestionably one of Flynn's lesser films. It is a bit slow in parts, and there are a couple of plot holes that one must overlook, but I found myself overlooking them and just watching the movie to be entertained. If one does this, the movie is certainly worth a viewing. I found Ruth Roman such a blessing, as she was not one of those melodramatic, chew-the-wallpaper actresses from the old studio system...she was grounded, strong, and REALLY beautiful. The rest of the supporting cast was pretty good, too. Raymond Burr is always fun to watch as a bad guy, and I enjoyed the two actors who portrayed the Filipino boys. Paul Picerni and Dan Seymour I found to be a little over the top, but not so bad that they were totally annoying or unwatchable. And, for me, anything with Errol Flynn is fun...even in a mediocre film...there is just something about the guy that I like.
I'm giving the movie a 6 out of 10 mostly because of the solid B-film performances, competent directing through most of the film (I think the flaws are derived from poor editing, not from the directing), and for the ever-enjoyable Errol Flynn. I think those coming to the film with realistic expectations, prepared for B-film entertainment, and willing to overlook the weaknesses of the screenplay, will find themselves in for an enjoyable film experience.