Conniptionfit is not a band you will ever hear about. They existed for a short period and released one demo (one member was also in a good death metal band known as Crucifix). The demo was a strange mix of old school death metal and hardcore. You could call it 'crossover' in the broadest sense of the term. The only comparison I can think of is Deadhorse (another Texan band), who played a similar kind of music on their masterful debut album. Conniptionfit sound basic by comparison, nowhere near the same league.
The individual band members sound like they bring different influences to the party. There are a bunch of death metal riffs (similar to Death, Possessed and Slayer), and some equivalent powerhouse drumming. The vocals vary, with some hardcore shouting and more guttural styles (sometimes edging into grindcore, particularly with the backing vocals and blasting). It sounds quite good when it gels. The band sometimes strings decent riffs together with some vibrant, lighthearted aggression ("My Will..." being the best example).
There is little substance here though. "Terminal Vibes" is fun and shows some interesting ideas within the chaos, but it doesn’t make much musical sense. The Minor Threat cover (of the iconic "Straight Edge") is the strangest moment. The band attempts to make the song their own, slowing some sections down to a sludgy, messy crawl, and speeding other parts into overdrive. Whether or not this cover succeeds is debatable, it sounds bizarre but I enjoy the impulsiveness of it.
The production is raw and unpolished. It sounds more like a punk production than a metal one. It was recorded by the guy who used to be the keyboardist in Absu (and he helps on bass here too). The band's carefree attitude is both the strength and weakness throughout this demo. Fans of the first Deadhorse album should probably seek it out for a quick listen, if only for the world's strangest Minor Threat cover.