When you say, "Undertow is quite different," it worries me a bit. Obviously because I am looking for more of the same . If Green has compromised his vision in any way just so it can fit the mold of a revenge drama then it's worrisome. It's a bit premature to comment any further without having seen the film.
I'm afraid you're going to go to see Undertow with the mindset of "I'm not going to like this, he's changed too much." And that's a shame if you do. But our mindsets don't always prove true. You may like it anyway. You, like many young idealistic film buffs, are far more pure than your idol, here. We can't really expect a director to keep making the same films over and over; only a few successfully do. If you admire him, why not trust him to do something different and still be good? I don't think you should feel that if your young cinematic poet learns more about how to make a conventional movie, he will somehow be ruined and corrupted. Incidentally, what's "the mold of a revenge drama"? Sounds like something out of the Elizabethan theater. I'm not sure there is such a mold, or that if there is, it affected Green in Undertow. The mold, if you want to call it that, is that he has a plot that pulls everything together, but as I've said, that doesn't keep him from his usual amiable and eccentric meanderings and observations or from his very keen and idiosyncratic sense of southern places.

I hadn't seen an interview with Green before. I'm interested in how new some of the basic techniques were to him, because he works outside the studio system and has made his own kind of (his term) "ruminative" movies.
One thing that was different is that a lot of the technical elements in the movie were new to me. Doing stunt work and doing more makeup, and using soft focus because the blood gags look fake, and being really particular about the color of blood. It's just a lot of logistics trying to execute stuff like that, action sequences and trying to make it safe. People did get hurt [nails in feet, broken ribs] and that's not good -- everybody was getting beat up and attacked, not only mother nature and the environment but by each other. It was a bonding experience.
Had he begun in B pictures or horror movies like Demme or Cronenberg he'd have had this background. In fact there's one shot when an object is picked up and looked at and it's got that greasy wet fake blood look, and time has passed, and real blood would have dried. But this interview shows how hard they all worked, especially since it was a low-cost production in rough locales. Of course, the list of Seventies drive-in movies was useful. I haven't seen them. Arguably not all great influences, e.g. the freeze-frames, but it gave him a tradition to transcend in his own way.

Also liked hearing how Jamie Bell clicked for Green and even seemed like the sort of person he himself was at that age. Bell clicks in the movie as I've said: he's perfectly cast. He sounds American but there's hardly any southern accent, probably desirable for Green who mentions he hates hearing fake southern accents (as do I, having grown up partly in Virginia myself).
iW: Do you want to do bigger budget films?
Green: Yes, I definitely want to do bigger budget projects.
Watch out! If you think he's been corrupted in this one, wait till he gets a bigger budget. I foresee a trajectory like Demme's. He'll be great when he gets bigger budgets and more access to known actors. He'll make his Melvin and Howard and his Married to the Mob and his Something Wild. And then he'll make his Silence of the Lambs and his Philadelphia and it'll all go dead. It'll be interesting to watch though. I'm surprised he's writing for Sydney Pollack and a "high concept studio comedy" for Seann William Scott. The dude's not so pure after all! He's obviously not working in a void in the bayou.