Minecraft's soundtrack and all of DK64
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Aurora3500
For me, it is listening to the 8 bit-style music that was common for NES games back in the day. Along with the gameplay of Arcade/NES era games being brutally hard. It takes me back to some of the classic Atari games such as Asteroids, Centipede, and several others which ended up being some of the 1st games I ever played.
TriforceShard
The Wii game "Spongebob Squarepants: Atlantis Squarepantis". My parents got me a Wii when I was 7, along with that game. It was the first real game I ever played, and is probably what sparked my love of gaming. I played it again recently, and I was surprised how familiar it felt. Granted, it's only been 10 years, but nostalgia is simply a matter of perspective.