I was surprised when I actually dabbled in x86 ASM (in the guise of MASM which arguably is a higher-level language than direct ASM) with BIOS and DOS interrupts as functions - it's quite close to C and not at all difficult - just tedious.

A powerful editor/IDE makes it ... not the worst programming experience in the world.

And since it's "so detailed" it's pretty easy to understand and explain, unlike higher-level languages that "do everything for you".