Who will fall for it?

[DarkN00b]

This is not "software", this is simply the library of Steam.

Let me explain some of you how it works.

Go to your Steam library -> Add a game -> Add non-Steam game -> Select any program on your pc -> Add selected program -> Now while it's in your library right click on it -> properties -> Now you can change its name and launch it.

Nothing illegal.

As you saw Kakkraft post. There was 'in-game Half-Life 3 blablabla'

Non-steam games got for example 'in non-steam game blabalbaba'
Thats how it works, so he is surely using software unless he has edited the image.