Retro means new things that look like they're old. As in "looking backwards" for inspiration. Like pixel art. Prime example: VVVVVV.
I'm mostly being pedantic, but it's a pet peeve of mine that gamers (and only gamers) use "retro" wrong. Every other type of collector correctly uses the word "vintage" instead: Vintage clothing, furniture, coins, wine, etc. And they use "retro" to mean new things that look old, like retro clothing. Only gamers call vintage things "retro".
In my experience when I point this out, gamers just get mad. I don't understand that. But I'm kind of a language nerd who watches linguistics videos for fun. And yes, I know language changes and evolves, and words mean how people use them, and dictionaries are not prescriptive, etc., etc. It's still wrong, damnit! It's a niche use by specific group of people that confuses everyone else because of its wrongness.