Hello, do downloads garuntee more plays, do they automatically update if the game is updated on browser, are they redownloadable, and how does this work?
It depends.
Most people tend to manually download games via web browser and obviously in this case if the developer updates the game it will not update unless the player manually downloads the entire game again.
Itch has an app that is similar to the gog or steam clients and can automatically update games, but it is not mandatory to use it so not everyone uses it.