Literalmente una Demo; como las que ya están implementadas.

Esta no es una función de Steam que se pueda añadir; es responsabilidad del desarrollador del juego. Muchos juegos ya lo incluyen; se llama demo gratuita.

Diskuid, yo propongo esto ya que no hay demos en todos los juego, solo en los más grandes (pero tampoco).

Originally posted by AdrianxosqyXD:

Diskuid, yo propongo esto ya que no hay demos en todos los juego, solo en los más grandes (pero tampoco).

Because they don't want to offer demo's and it's their right not to offer demo's if they so wish. Making demo's cost money, time and resources better spend elsewhere.

Steam already offers the developers and publishers ability to offer demo's, parts or entirety of their games for free. Many episodic games for example offer first episode/chapter of the game for free. Another example are games with free base game that make money from DLC sales like Order of Battle: World War II:

(Edit: Apparently there is an issue posting game links on posts currently. All text disappear from the post if I post link as is. Putting the link inside a quote seems to resolve the issue)

https://steamhost.cn/app/312450/Order_of_Battle_World_War_II/

Base game contains tutorial campaign and 1st scenario of every DLC campaign for the game.

As you can see Steam already offers the features you suggest and more as is. It's developers/publishers choice if they want to use any of those features or not. Valve will not interfere with development of 3rd party titles, it only offers optional features for them to use.