November is rather heavy for its time, mostly hard rock but definitely some metal parts as well, lyrics are swedish. A real gem of 70s hard rock for sure, with more legitimacy than most supposed "proto-metal" albums.
Demon is basically a mix of straightforward hard rock with some metal mixed with prog rock, think Deep Purple but more AOR, with charismatic mid-ranged vocals. It's also one of their best albums, so a good starting point if you're not familiar with 'em. Just don't expect something super heavy.