This is not a list of my favorite video game music tracks, but a list of those I catch myself hum from time to time, that are forever engraved in my brain for some reason.
FFVI's Shadow's Theme:
YouTube - Final Fantasy VI Music - Shadow's Theme
Is it the Morricone-esque mouth harp? The slow theme? I don't know. It's stuck.
Silpheed's Stage 10:
YouTube - Silpheed Music - Stage 10
This track is a mess but memory has a way to clean things up, so its kind of solemn melody got engraved and the rest vanished.
Gradius 3's Boss On Parade part 3: 3'30'' into
YouTube - Gradius III BGM : Boss on Parade
This is a very short loop, but the bass line got trapped forever between my ears.
Actraiser 2's Death Field:
YouTube - Actraiser 2 - Death Field & Almethea
30s loop, but the resolute tone of this march (is there any military march that is not resolute though?) cemented it in my cortex.
That's only 4, so as a bonus a nostalgia moment:
The intro of Ys I on PC-Engine CD-RomRom YouTube - PC‚ƒ‚ƒ €Œ‚ƒ‚…ƒ…€ ‚ƒ‚… OP
Discovering this in an import shop at the tail end of 1990 along with the Super Famicom was a shock. In fact the beginning of the video still gives me goosebumps.