Unity and Unreal both have HTML5 as a first-class platform, I believe.
What webasm will do for games:
- Not much for graphics, those are limited by the graphics APIs
- Maybe allow number-crunching of 32-bit floats and integers to be faster because you don't have to fight JavaScript's native types being doubles
- Reduce overhead because the runtime doesn't have to keep track of its own GC, or things like falling back to a slow interpreted path (which takes some memory, even if the fallback never happens)
- Allow stuff like Unity's C# runtime to be more efficient, since it's just running the C# runtime directly in webasm instead of using something like asm.js where it has to sit atop the larger JS runtime and its GC
It's gonna be nice. There will be complaints, and backlash, but nobody could have prevented this, and it is a benefit to many use cases.