The best thing about Queen albums is that they are all over the map.
One never knows what to expect. A piledriving rocker can be paired with a show-stopping Broadway number, which can be followed by an acoustic ballad and then a disco song. It's one of the things that makes this band so hard to categorize and so fun to review, and it only could have happened in the '70s.
Before "Bohemian Rhapsody" and "Another One Bites the Dust," though, Queen was essentially a hard-progressive-rock band. 
Sheer Heart Attack showcases what the band would soon become while giving a nod to their hard-rock past, serving not only as an important transition album but a fun listen as well.
Freddie Mercury opens with a falsetto in the driving "Brighton Rock," which careens from majestic vocal harmonies -- a hallmark of the band -- to Rush-like instrumental interplay on the verses. Other highlights on the first side include the hit "Killer Queen," a perfect little rock song with a calculated guitar solo and Broadway-like vocals; the White Album-esque leftover "Tenement Funster" and "Now I'm Here," which should be familiar to every Queen fan, what with the vocals jumping around on both sides of the speakers and an understated intro that gives way to a sonic assault that would make any rock band proud.
Queen somehow manages to sound like every rock band of the '70s on here, including Rush, Zeppelin and even Uriah Heep ("In the Lap of the Gods"). The difference is that Queen actually tries to be pretentious and bombastic, and often times they are so over the top one can't help but be entertained. But again this band manages to surprise, especially on the second side -- the bombastic "Lap" gives way into the excellent, kinetic heavy-metal-foreshadow "Stone Cold Crazy," while the hymn-like "Dear Friends" gives way into the pleasant acoustic of "Misfire." And although the vocals are a bit annoying on "She Makes Me," the echo on the drums and guitar is too catchy to ignore.
The filler tracks here are still better than anything Queen created in the '80s, even if the lyrics don't always make much sense, and the band's instrumental work rivals anything put out in 1974. This is not Queen's best album, but it's their most fun and showcases everything they did right.