"What a legendary band Celtic Frost was. It emerged among the originators of extreme metal, yet it quickly became a one of the first experimental bands in the metal circles. "Into the Pandemonium" is rightfully considered by many as a one of the earliest avant-garde metal records. Of course, it's not that avant-garde by the modern standards, but back in 1987 it demonstrated the extremely specific eclectics. Interestingly, many conservative metal enthusiasts fail to understand "Into the Pandemonium" even today...

Thus, "Into the Pandemonium" mixed thrash metal with gothic rock, post-punk, symphonic and orchestral music. Today people would have labeled the album as thrash / gothic / symphonic metal, but obviously it couldn't be perceived this way in 1987. "Into the Pandemonium" deserved the avant-garde status with its extremely innovative eclectics by the standards of 1987. Apart from innovation, influence and other stuff, "Into the Pandemonium" is just a genuinely interesting work to listen to, memorable without a doubt."

- HviteGuden, metal-archives.net