In brief: It looks like Serious Sam 4 will only be available on PC and Stadia — at least at first. Shortly after the game was announced with a short teaser in 2018, the little information we were able to get on the title since indicated Croteam would developing it on all platforms. That has not changed, but when PlayStation 4 and Xbox One will get it has.
Google was able to convince publisher Devolver Digital to make Serious Sam 4 a Stadia exclusive for one year. This agreement did not affect the PC release.
On Wednesday, Croteam announced that the game was coming to Stadia, but did not mention it being an exclusive. Devolver Digital told Kotaku that it still plans to release the title on home consoles, but has put that off until 2021.
"The game is still coming to Xbox One and PlayStation 4 after its period of exclusivity is over with Stadia," said a spokesperson.
Along with the announcement, Croteam released a new trailer with Sam riding a Sirian Werebull into the camera. In addition to the teaser, the studio dropped several clips of gameplay showcasing battles, enemies, weapons, and game music. It also gave a quick intro into something it calls the "Legion System" (video above).
According to Croteam's Graphics Engineer Dean Sekulić, the Legion System allows the game to have "hundreds of thousands" of enemies on the screen at once.
"We were really pleasantly surprised at how fast it can run," said Sekulić. "Originally, we were hoping for like 10,000 enemies, and now we have hit an order of magnitude more."
Devolver does not have an exact release date nailed down yet, only saying that it was coming first to Stadia and PC in August with PS4 and XB1 versions arriving next year.