Splinter Cell: Chaos Theory is nearly 20 years old and still looks great.

Mass Effect 1 & 2.

I was finding new conversation snippets for years after release. It was as if Bioware was downloading new content in the background.

I didn’t hear Mordin sing ‘Scientist Salarian’ for ages after I bought the game, and I’d had ME1 for years before finding ‘The Negotiator’ quest because you need 80% Renegade for it to trigger.