Screenshot of the Resident Evil Village online demo webpage.
“Instantly” is only a slight exaggeration.

The demo of Resident Evil Village is powered by Stadia and allows people to play the game in a browser. No matter what device they own, people will be able to try out the game, according to the press release. Anyone can try out the game for free if they have a supported web browser and an internet connection that is at least 10 megabits a second. To play the game, you just need to navigate to the website, enter your birthday, and click the play button.

You get what you paid for with the browser version of the demo. There are two versions of the demo, one on the left and the other on the right.

The images from the cutscene look relatively similar.
When it comes to gameplay, however... to quote another one of my coworkers tried the Stadia demo: “just tried it. looks like shit lol”

I admit that the demo let me know what Village is about, but I mostly care about story and game mechanics. I didn't have to download any data to play it or worry about my computer's capabilities, I just clicked the button and played it within 90 seconds. The demo warns that it may use a large amount of data if you play it for a long time. The content of the demo is the same, but the hour-long time limit has been removed.

Stadia branding isn't the first thing that comes to mind when you think of in-browser games. Other companies can white-label the tech behind Stadia if they use something called Immersive Stream for Games. AT&T gave its customers access to a streaming version of Control Ultimate Edition and Batman: Arkham Knight before that.

While Stadia has demos of its own, it seems like the idea has more of a future as a white-label product that companies can use for demos.

There is a difference between instances of the tech behind Stadia being used for demos and the demos that are available on the service itself.