Google just moneyhatted Serious Sam 4 to keep it off consoles, so they could have it exclusive for a year. Yeah, you heard that right. They are starting to pull the same exclusivity shit that EGS has been pulling on Steam. Except they are targeting consoles. This is going to be a really shitty gen if every other 3rd party PC game is locked to the EGS for a year, and every other 3rd party console game is locked to Stadia for a year.
But they don't have it exclusive for a year, thanks to the PC version.
The only game (timed?) exclusive to streaming platforms is "Gylt" as far as I know.
I played through that in my free trial of Stadia... a nice exploring game, but no system/service seller. It ran very well, but that can be expected for slow paced genres like these.
On the other hand I can't understand why Google thought that fast paced games like Mortal Kombat, Thumper or Serious Sam would be good fits for their service.