Announced several years ago, Synapse Films' special edition of Curt McDowell's underground epic THUNDERCRACK! finally hits Blu-ray stuffed to the gills with extras.

THUNDERCRACK! opens on a storm-swept night in the Midwest as seven motorists end up at the Prairie Blossom estate accepting the hospitality of widowed Gert McCarthy (Marion Eaton, BABYFACE) – who introduces herself with the surname of her preferred suitor Charlie Hammond – when the bridges wash out. Insatiable Roo (Moira Benson, RENDEZVOUS WITH ANNE) and red-assed Sash (Melinda McDowell, the director's sister) overturn their car while teasing horny hitchhiker Toydy (Rick Johnson). Hustler Bond (Ken Scudder, BABY ROSEMARY) and effete Chandler (Mookie Blodgett) – his sexual desire deviated towards males after witnessing his wife's fiery death by exploding girdle – are stopped by country rock singer's virginal wife Willene Cassidy (Maggie Pyle) to rescue them. Bing (fellow underground filmmaker George Kuchar) overturns his circus van. The sex-starved Gert pickles her cucumbers while spying on the sexual shenanigans of her guests was they change into dry clothes in the sex toy-filled bedroom belonging to her sixteen-year-old son who has ceased to exist since his ill-fated expedition to Borneo. Sexual tension builds up and explodes into various couplings (including a couple in the cellar where Gert's late husband's remains are pickled after he was devoured by locusts), but a greater threat comes the Medusa (Pamela Primate), an over-amorous, bloodthirsty gorilla with a taste for virile male flesh who has escaped from Bing's van.

Seemingly a pornographic homage to 1930s horror films like OLD DARK HOUSE (and many other "old dark house" films), and perhaps bearing an unintentional resemblance at times to some of Andy Milligan's early works (particularly SEEDS OF SIN), THUNDERCRACK! was the fourth feature of underground filmmaker Curt McDowell (TABOO: THE SINGLE AND THE LP), co-written by Kuchar who also collaborated with McDowell on the film's special effects. The stormy exteriors and tortured psyches of the characters are illustrated through animation, miniatures, and expressionistic vignettes superimposed over their tormented faces. The sex scenes encompass everything from sex toys (makeshift and otherwise), bacon grease-assisted anal sex, love dolls, masturbation, straight, lesbian, and gay encounters, and even simulated bestiality. The sense of perversion underlying the less "conventional" sexual desires seems to be not only a swipe at conservative attitudes of the time but also reference to sexuality as psychopathic pathology as depicted in films of the earlier half of the century. What surprises most about the film is that it remains compelling even as it gets sillier and sillier. The closest thing to THUNDERCRACK! that the uninitiated cult film fan might recognize might be the 1990 Greek softcore sex and gore neo-noir SINGAPORE SLING.

According to composer/actor Mark Ellinger in the "About the Transfer" booklet, only five 16mm prints of THUNDERCRACK! were struck. One was trimmed by the distributors to ninety minutes, a second to two hours, a third was seized by Canadian customs, and a damaged fourth print was the source of a Scandinavian DVD release of the shorter two hour version. The fifth print used for retrospective screenings has accrued damage over the years and has undergone extensive digital clean-up here with missing footage restored and reconstructed from other audio and video sources. It really sounds worse than it is since Synapse's 1080p24 MPEG-4 AVC 1.33:1 pillarboxed transfer of the full version (159:26 with full ten minute intermission) looks quite nice overall given the stylized look of the film. Some shoots look like they were filmed yesterday, some look like restored prints of vintage film noir expressionism, with the worst of the damage being fairly minimal. The English DTS Master Audio 2.0 mono track has also been cleaned up but will obviously never compare to a studio's mono mix from the period. The disc also includes optional English SDH, French, German, and Castilian Spanish subtitle tracks.

The first eighty-five minutes of the film is accompanied by a vintage audio interview with director McDowell from 1972 (predating THUNDERCRACK!) in which he discusses initial desire to be a painter and his schooling including a lengthy discussion of school politics and the focus on the ability to pay tuition over talent, as well as those on the faculty who encouraged or discouraged students. He goes on to discuss his paintings as well as his interest in photography and filmmaking, and how he discovered that filmmaking encompassed all of his interests. He also covers his film schooling with a humorous anecdote about his first class and how he ended up as the school's most prolific filmmaker despite a discouraging beginning, as well as his first hour-long 8mm film shot during the school break that shocked its audience with real autopsy footage. He goes on to discuss exhibiting his early works, moving on to 16mm, and the need for increased technical proficiency as his work became more ambitious, moving from the label of "underground filmmaker" to "filmmaker". The only other on the first disc is the 2009 feature-length documentary "It Came From Kuchar" (86:25) – an exclusive to the Blu-ray release – by Jennifer M. Kroot (TO BE TAKEI) focusing on Kuchar (who died in 2011) and his twin brother Mike (SIN OF THE FLESHAPOIDS) with commentary from Melinda McDowell, writers Buck Henry (CANDY) and Whitley Strieber (COMMUNION), as well as filmmakers John Waters (PINK FLAMINGOS), Atom Egoyan (EXOTICA), Guy Maddin (CAREFUL), Christopher Coppola (DRACULA'S WIDOW), Wayne Wang (THE JOY LUCK CLUB) and Jonas Mekas (WALDEN). McDowell and Eaton appear via archival footage.

The bonus features DVD starts off the theatrical trailer (3:28), the narration of which makes it sound more like a 1960s roughie than an underground art film. Kuchar appears in an interview (10:24) in which he recalls student McDowell whose films he felt celebrated the more fleshy aspects of life, with THUNDERCRACK! as a drama about people working out their sexual traumas (with Kuchar working in his own "sexual turmoil" in composing the script from McDowell's skeleton scenario). McDowell saw sex as a "joyful union" while Kuchar saw it as horrific and obsessive, and that hardcore sex was too powerful to be shown since it distracted from the plot. From 2004 comes "Marion Eaton Recalls Gert Hammond” (5:38), in which the actress recites a letter she has composed about her experience on the film, including her favorite scenes and lines (the "maple tree" speech). Co-writer/compose Mark Ellinger (RESURRECTION OF EVE) appears in the 2004 interview “Recalling THUNDERCRACK!!” (8:24) in which he discusses his and McDowell's shared love of black and white film, film noir, and "old dark house-type mysteries." He also discusses scoring the film and shed light on the condition of the remaining prints of the film. McDowell and Eaton also appear in 1976 interview for a program on San Francisco Bay Area Filmmakers (23:04) in which the director distinguishes his X-rated work from pornography while Eaton discusses how incorporating explicit sex into her performance was an opportunity for greater intimacy in shaping a character who she sees as a tragic one (with her vomiting scene harder to do since it was hard to find the beauty in it).

The outtakes & behind-the-scenes footage section (29:46) includes unused takes, a few unused scenes (Willene trying to distribute autographed photos of her singer husband before dinner), alternate line readings, and glimpses behind the scenes as some of the flashback material is set up, as well as a couple blown takes of Gert trying to castrate Toydy with a cleaver (takes of the accompanying insert shot are included in the accompanying sex scene outtakes (17:29) segment. Partially accompanied by sound, the sex scene outtakes include alternate takes and angles for three of the sex scenes, as well as a couple takes of Benson taking a facial from Johnson. The cast audition footage (8:38) is presented without sound, with several of the actors who ended up in the film along with some that did not reading dialogue (alongside Melinda McDowell) before stripping off for the camera (with one or two looking less comfortable but going ahead).