We actually really want to build web version, but unfortunately godot 4 c# still doesn't support it T_T
https://godotshaders.com/shader/billboard-grass-with-wind/ - here resource that we used for grass. Its actually pretty simple and there a lot of other similar implementation for beautiful grass!
(Game actually 3d with AnimatedSprite3D used for 2d sprites. Allows cool grass overlap + shadows.)