half life is a fab choice!,i havent played it for nearly twenty years but ill never forget gordons useless but very iconic crowbar.
for me,its either old nostalgia-when i play sixteen bit goodness such as sonic and hitting up green hill zone-that music,the colours, the sound effects...all bring me back just thinking about it now.
or newER nostalgia really-its not very old but panzer dragoon saga, any part of it brings me right back to the hidden and widely undiscovered beauty of the sega saturn but theres a piece of music in the OST that really hits me deeply and entrances me in nostalgia,this particular piece is very emotive,-its right at the end of disc 1- go to youtube and search for a track in the game which is called
pure blood seed, honestly-its beautiful,melodic and emotive-and it brings me straight back to the level-i can see everything happening without looking,i can see it in my mind, and it makes me feel quite a lot of empathy for these polygonised dragons getting hurt-but i also feel so lucky that i got to play this game and have it as part of my gaming CV,truly a beautiful game itll never get old.