I don't usually remember music or even listen to music, it's one of the things I'm most incapable of talking about. For me, I feel it's somewhat the other way around: without a track being tied to a particularly lasting emotion or memory, or some very distinctive characteristic like Hirasawa's style, I find it very hard for it to stand out. One of few themes that for last five or six years I've had etched into my soul is that of God Hand's demons' due to the sheer terror of facing one of these motherfuckers, and the intentional mood whiplash their appearance generates as all of the environment darkens and enemies stop to orbit around you so you can focus on dueling the fucking hellspawn coming to destroy your ass, heralded by a very specific SFX I can also distinctly recall. This is the theme, for anyone who hasn't heard it:
https://www.youtube.com/watch?v=ePWs5nRytC4I very rarely listen to it, yet the feeling is immediately fresh whenever it comes to mind. God Hand is a very lighthearted game with tons of silly carnival variety thrown around and the OST reflects this, it's got like fifteen different styles in it. I suppose it ties into the reason why the band I've listened to the most is by far They Might be Giants, it's a world of difference whether you're listening to Climbing the Walls, Boat of Car, Vestibule, or End of the Rope, that's what truly stays with me. I think it's rare for media to have an OST with multiple salient yet commonplace tracks in this way, as (in my experience at least) it's usual for the odder stuff to be relegated to smaller sections and not as prioritized as the bigger themes you'd expect, compare this to Berserk with Hirasawa which I already mentioned. It helps that these are VERY popular themes. When watching Nige-Jouzu I also noticed the tune and relevance of the track you talk about, but its actual sound I forgot around a minute later.