It was a huge relief, because there was plenty at stake. First off, who were these New Zealanders who thought they could impress an American audience with a Western?
Then there was all the money they had set aside for a home but had instead poured into a childhood dream. Not to mention the possibility that the audience or even the New York Times reviewer might have taken offence at the somewhat dodgy plot.
Worried?
"Well," says Wallis, "I still think about all that stuff every day and we talk about it all the time; all those doubts about the story, what we were doing, and the 'oh my God, what are they going to think?'
"While those doubts are still there - there were late nights staring up at the ceiling - we never stopped believing. But that didn't stop me from gripping my seat the whole time [at the premiere]. It was a pretty uncomfortable watch. I mean, waiting for [the lead actor's] first line ... and they laughed. They laughed in way more places than I would have imagined. They got it and that's an incredible feeling when you're [living] your dream. It's a really intense mixture of emotions."
You've got to hope Wallis enjoyed the experience, because he'll go through it again when the movie goes nationwide in New Zealand cinemas on May 3. This time he has the added challenge of convincing local doubters of the merits of his lifelong obsession: the Pavlova Western.
Wallis grew up in Dunedin but it was the open spaces of central Otago that brought his inner-cowboy to life.
He'd always adored westerns. Nothing could beat posses hightailing it to the pass, gunfights over sleeved aces and white hats versus varmints for thrills, and it all came to life whenever his family holidayed in those empty hinterlands. Add a stagecoach and a few Apaches and it was the Wild West Downunder.
His enthusiasm was raised further when a job in a Queenstown video store turned him on to Sergio Leone's morally vague Spaghetti Westerns. Each return trip to the empty highlands conjoured a new movie in his imagination.
"This was all before Peter Jackson made The Lord Of The Rings. Until then, as far as I was concerned, making movies wasn't a viable reality."
Instead, he did the next best thing and ended up landing a job with Weta in Wellington, working his way from production assistant and runner to animation co-ordinator on films such as Avatar, King Kong and The Day The Earth Stood Still.
He also met Inge Rademeyer. After completing a degree in film at the University of Auckland, she danced with the Black Grace Youth Movement and did some cheerleading for the Breakers and Sky City troupes.
Mutual friends got them together in 2004 and they conducted a long-distance relationship until Rademeyer got her own job with Weta and headed south.
They were engaged five years later and Wallis took his bride-to-be to Central Otago, where he shared his childhood dreams. Then they returned to Wellington to buy a home and get on with a normal life.
It was while driving away from their third failed house-buying attempt that Wallis spilled his guts. "I'd come to a point of 'what do I really want to do?' Almost reluctantly I said, I'd love to make a Western..."
"Okay," said Rademeyer, "let's do it."
Their home deposit had suddenly become a movie budget.
"I figured that if it all goes wrong, we're young enough to make it back again," says Wallis.
"And it helps that we're all-or-nothing people," adds Rademeyer, "so when we decided we were in, we were all in. And in a way that kind of made things easier. When you've put everything you have into something then the demands of that project sort of makes all the decisions for you."
Being self-funded, it was only ever going to be a low-budget exercise, but Wallis knew that a landscape as photogenic as Otago's would give them top-flight production values very cheaply.
And Rademeyer was gagging to be his leading lady, Isabella. All they needed was a story.
After years of fanboy viewing, Wallis had very strong ideas on what made a good Western. Basically, it's a journey through a lawless world filled with tension and sudden violence that forces characters to come to their own moral realisations.
And that's exactly what he's made, with plenty of dry New Zealand understatement, black humour, the long, silent stares of Leone's epics, and - uniquely for a Kiwi movie - not a single sheep reference.
There are no snakes either. Wallis dropped an idea to use the sound of a rattling rattler.
But what drives his movie along is the plot, and it's sure to get a response.
Let's just say The Man (he has no name, nor back story) has a lousy attitude towards women - and people in general - and after a swift bit of murder his desperation to use her for his own ends is stymied by a rather un-cowboy failing. Wallis and Rademeyer refer to the vital moment as "the attempted scene".
The Man then drags her hither and yon in search of a cure for his sexual dysfunction.
Understandably, Wallis was a bundle of nerves when he presented his partner with a draft of what he had in mind for her.
"He was watching me read," she says, "just pacing around and watching. I had to tell him to go away ..."
With her approval, the next job was finding the right actor to carry off a role that is unsympathetic and practically silent. A comedian would do nicely.
"We watched Eagle Vs Shark," says Wallis, "and I walked out thinking the geek was great. It turned out Inge was thinking the same thing. We just felt [Cohen Holloway] gave a really subtle, understated performance and he has this unusual charm about him."
"I heard they were casting through a friend of mine," says Holloway, "and that they were interested in me, but I have to say I've got no idea how they connected those two roles together. Then, as it turned out, I was the first to audition."
It was a major step for the actor who'd graduated from the New Zealand drama school only five years earlier and was known mostly for his impressions on the TV One comedy, Facelift.
Up until then he'd sung with Little Creatures, a band who were regulars at the Mountain Rocks festivals in Manawatu. He turned to acting after an altercation with the Mongrel Mob in Hastings. Which is all very rock 'n' roll, but not enough to make playing The Man any easier.
"Morally, I had some real issues with it and I had to talk to Mike about that. How can he redeem himself? And how can anyone get on board with him?
"As a metrosexual myself ... heh... some of the language was pretty hard to deliver and the big scene really wasn't my cup of tea. The only way I could rationalise it was by accepting him as the product of his environment. He knows no better."
Then there was the matter of his silence. His first words don't arrive until almost 20 minutes into the film and even then they're barked grunts. It took a lot of rehearsing before he felt the camera would be able to read his expressions.
If his creation seems awkwardly familar, that may be because Holloway was channelling an extreme version of your rugby-headed, Southern man. Anyone taking offence can be reassured that some karma was dished out.
While shooting one of the confrontations between The Man and Isabella, he endured 15 full-blooded slaps before they'd got it right. And Rademeyer knows kung fu. "At one point she was fully airborne when she hit me ... that really hurt. Then she had to do it again because Mike thought it wasn't how a lady would fight."
But the pain was worth it.
The funnyman has developed a sexy, brooding presence capable of dark drama and once that shoot was done he was immediately cast as David Dougherty in the telemovie Until Proven Innocent.
"I was really nervous when I got the role of The Man, but it's given me so much more confidence," says Holloway. "But for the record, I'd still say comedy is harder." He even got an ovation during the Q&A in New York when the audience heard he didn't use a double for his bum shot. He's now keen to try his luck in Hollywood.
All the best to him then, but I hope he doesn't mind me saying that one of the best performances in the entire movie comes from someone we never see.
John Psathas' soundtrack is all over this movie, he is the Ennio Morricone to Wallis' homespun Sergio Leone.
"From day one," says Wallis, "we knew the music was going to be key. We already had the NZSO on board but from the moment he came on board we felt really safe ... that was a huge coup."
Originally one of Psathas' students in Wellington had the job but he dropped out after being headhunted by TV3.
Many movie-makers have tried to get Psathas - who wrote the opening and closing fanfares for the Athens Olympics - to do a soundtrack and been politely declined. But he was intrigued enough by the concept of a Kiwi Western to watch a cut of the finished movie and fell in love with the notion.
When combined with the widescreen natural beauty of the locations it sounds like a million bucks.
Which brings us back to money... Rademeyer and Wallis would really like you to see their movie. And maybe take a friend. That way they may be able to pay everyone who worked for them.
Even Holloway elected to flag the pittance he'd been offered in favour of the Star Wars option of a point share of any future profits.
Serious cost-cutting was the only way the film could be made.
During the three-week shoot in the South Island, the volunteer crew was accommodated and fed by Wallis' relatives, the props were collected from junk shops, a herd of buffalo was borrowed from a Frenchman living near Christchurch and the Mellonsfolly Ranch near Ohakune served as their frontier town. Wallis even spent a
year at a Wellington gun club to qualify for an amourer's licence so they wouldn't have to employ one.
That turned out to be a great move. Months of playing around with vintage cap and ball revolvers taught him how much smoke and noise they made, as well as how the difficult they were to load and shoot straight.
These lessons inspired the movie's unusual shootouts, one of which was filmed in a set whipped up in the nick of time by some very handy friends at Weta.
But even after all that slog, they still lacked the cash needed to get Good For Nothing into cinemas.
Cue Academy Award-winning film editor and producer Jamie Selkirk riding over the hill, his saddlebags loaded with $750,000.
Wallis had approached him for some editing advice and he liked what they were doing so much he wanted to ensure it would be seen. He even accompanied the pair to Santa Barbara, when they were invited to hold the movie's world premiere at their festival.
Nothing opens doors like having an Oscar on your team.
So, it's six years since they failed to buy that house and the couple's families will finally get the chance to see what they spent their money on instead.
"Oh, there were times when we wanted to kill each other, but neither of us ever wanted to stop," says Rademeyer.
"And I could never get sick of it," says Wallis. "If I love this world I have created, and I do, how could I get sick of that? It's fun, it's gritty, it's dangerous and it's what I've always wanted to do.
"Anyway, I won't feel like the film is finished until it's out there and it's got a life beyond the making of it. Then we have decide if we'll do another one ..."
Check out the Good for Nothing trailer below:
Good For Nothing is at cinemas on May 3.
