How to install a demo instead of a full game [Shitty giveaway inside]

So some people enter the giveaway without trying to answer your question and not even bumping the thread? That's a shame. Here, let me bump that.

Perhaps seek out a source of the demo outside of steam? After, demos are only promotional material and are probably more readily available such as at the publisher's website.

Steam games sometimes have a certain install codes, which you can enter via Properties -> Betas tab. But that depends on what game and if the devs actually use that feature.

As far as I know, the Stanley Parable demo is not exactly a demo of the game but some sort of prelude and that's why it is a seperate download/'game' and can be donloaded seperatly to the game itself (at least as far as I know). Might not be possible to install a demo of an owned game if the demo actually is the game but with cuts or a timing restriction.

Steam accounts are free. Roll up a new one and install the demo.

cant you use the appid url?

steam://install/12345 whatever it was

edit: you would have to know the demo's id... use steamdb i guess

There's only a handful of cases where this is possible. Teh Stanley Parable is basically a standalone game and Ustoppable Gorg demo can be played by installing on a second account other than that though and maybe another couple I'm unaware of if you own th game you can't play the demo

I cannot help You but bump :)

pick the game, remove it from your steam account, download ithe demo, restore the game, PLAY IT!