Musically this is a pretty amateurish effort. Production-wise, the overall sound is relatively thin, with lots of reverb for atmosphere. Guitars buzz along with thrashy riffing that has its roots in Venom and Motorhead, while the bass rumbles underneath with simple bass lines. The drums keep simple, fast beats and do nothing else, as this album was recorded using only snare and bass drums and a crash/ride cymbal.
That said, this debut from Bathory doesn't seem like much when compared to later masterpieces like "Under the Sign..." and "Blood Fire Death". However it is one of the most important albums in extreme metal, as it was one of the first that helped set the standards for what would soon become known as black metal.