It’s been said before, it will be said again, people will say it for years and years to come. Shows at the fringe shouldn’t last more than 90 minutes.Of course this isn’t a hard and fast rule. There’s a theatre show that is going on all night, there’s a dance event that goes on for as long as you can dance; the fringe is open to all sorts of new drama and new possibilities and there should be allowances made for very long or very short drama. But if you’re going to jump over my 50-minute attention span - let’s be honest, you’ve developed it here too - then you better be doing something pretty freaking incredible.This production of Moll Flanders isn’t awfully executed, but it’s not amazing either. It’s not a brand new adaptation, but its cast just isn’t up to standard. Everybody except Suzie Marshall, that is, who is fantastic in her portrayal of Flanders herself. The story, if you don’t know it, is about a girl born in Newgate Prison, who sleeps her way around society, eventually descending into thievery again. That’s the Cliffnotes version. Edinburgh Theatre Arts have the two-and-a-half-hour version.The problem is the ensemble seems too big, considering some actors take up three or four roles, and others only one or two. They’re of wildly varying ability, some unable to decide what accent they’re trying to put on, others failing to provide basic skills on stage. And don’t get me started on the songs.Okay, I am going to get started. We’re presented this play in more of a musical format, though without band, and without expectation of applause after each song. The a cappella numbers are sometimes well-executed, but to be frank, you shouldn’t sing a cappella unless you’re incredible. It’s difficult enough to do, and singing in key seems to be a privilege reserved only to a few people. Otherwise, expect every other note to be met via glissando. It’s all a nice idea, just not a great execution.If you love Daniel Defoe’s novels, then you’ll want to see this, and I don’t want to tell you not to. It genuinely can be enjoyable, especially Marshall’s performance. But if you don’t, you’ll find much better works out there, and trekking across Edinburgh to this production really won’t be worth it.