It can be so loud and overwhelming, the guitars ringing in your ears, the drums and the bass pounding at your skull... But then there's soft melody and peace.
The lyrics are great, each song is a different story written very poetically. These songs aren't written anything like typical pop or hip-hop lyrics, it feels so intimate. Like you're being told a story by the campfire, or just an account of events, except there's blaring guitars. The vocal delivery matches the instrumentals: overwhelming and intense, or quiet spoken-word.
It's hard to put into words exactly how I feel about this album. I think the song Don, Aman is the best example of what makes this album so great. It's like the calm before the storm when you're alone on a rocking boat, that intense feeling of tension, expectation, waiting for things to fall apart when there's nothing there yet. And it's lonely.
I guess underrated was the wrong choice of words. It certainly is less well known than it deserves. Slint only had 2 records and in fact had broken up before this album was actually released so the record label basically just gave up on promoting it. It certainly was an influential album and is now getting the praise it deserves (32 years after it was originally released).