The SID sound chip gave us dozens of memorable musics for the Commodore 64 games. These musics came by the hands of the tallented (and usually young) musicians that worked with the chip back in the 80s. Among them, one of the most brilliant (and my personal favourite) is the Dutch founder of Maniacs of Noise, Jeroen Tel.
Some of his most famous soundtracks include those he wrote for Cybernoid and Cybernoid II, Myth, or Eliminator. And in my opinion, Savage's music is awesome. Here's a list of most of its tunes for C64 games.
Recently, Maniacs of Noise released a new C64 demo, that is actually a compilation of some tunes of the group: