Two high school metalheads play a forbidden piece of music that unlocks the gates of hell. Now the two headbangers and a metal maiden must join forces to save their town from a demonic onslaught. —Amazon.com
“lower case if for pussies.”
No need to search for motivations here, it’s all pretty clearly laid out. The devil is here and it’s up to the local metalheads to save humanity. Excellent humor, excellent acting.
Also, this is an actual scene in the movie: 
The “random” orientation of pentagrams, is annoying…