AUSTIN, Texas — The moral compass of a silver-screen superhero almost always orients to “stoically law-abiding.” But for filmmaker James Gunn, superheroes exist in an uncomfortable twilight between levity and brutality.

It’s only been 16 hours since his low budget anti-superhero black comedy Super played to an enthusiastically packed house at South by Southwest. Though pleased by the response, Gunn isn’t one to take a self-aggrandizing victory lap for the little guy. In fact, the sardonic director says big-budget, blockbuster-minded superhero flicks still have a rightful place in Hollywood.

“Superhero movies are just an incredibly fun space to play in,” said Gunn, while poking at his lunch in the corner of a shady Marriott diner. “People like me love reading comics because we get to see these guys fly around in space and blow shit up, and technology has finally reached a point where what exists on the page looks good on the big screen.”

Gunn’s niche indie flick, which opens April 1, had a rougher time taking flight than movies based on popular comic book characters. His gleefully violent script about a jilted husband who seeks redemption through vigilantism as The Crimson Bolt was well-received by the film’s first batch of producers.

Even the somewhat risky, genre-bending nature of the story wasn’t a problem; former Troma Entertainment writer Gunn had already proven his acumen in balancing wildly varying tones in 2006’s critically acclaimed (but financially shaky) horror/comedy Slither.

But as the producers pushed for casting a traditional leading man to play Crimson Bolt, Gunn eventually had to part ways amicably. To pull off Super’s deliberately uneven vibe — from bone-crunchingly brutal to unabashedly funny to overtly sexual, all in one go — Gunn was going to have to buck the conventions he’d grown to love as a comic book nerd and an indie filmmaker.

“From the beginning, I saw the script as an arthouse/grindhouse film,” said Gunn. “To start to think that we’re going to turn this into the next My Big Fat Greek Wedding is unrealistic. It’s not an independent movie that gets big, it’s actually an independent movie.”

Armed with a new batch of producers and a charismatically clunky leading man in Rainn Wilson (The Office), Gunn was free to chase his vision — one famously described by Wilson as a “fucked-up, low-rent Watchmen.”

Even with the success of Saturday night’s U.S. premiere behind the visibly exhausted Gunn, the acerbic filmmaker isn’t pulling punches regarding some of Super’s big-budget brethren.

“Warner Bros. is obviously fucking up,” Gunn grunted as he pushed his lunch aside. “They don’t know how to make a good superhero movie unless Christopher Nolan is involved to save their lives.”

However, Gunn says the genre still has a glimmer of hope in Joss Whedon’s forthcoming The Avengers flick.

“Everybody I know who’s read it says it’s by far the best script for a Marvel movie ever,” said Gunn. “I’m very, very excited about it. Nobody loves superheroes more than Joss. He’s really got his heart in the right place.”