Nothing against to post always free games, I think. On Steam there are a lot of free games, but a lot of them are not really free, being either extremely short, they are just prologues to a series that later costs a kidney and a half or simple demos.
I think this is why there is nothing against posting free games that are worthwhile, offering a good time of gameplay.
What's more, in the past I have come across a Demo, 'Will Rock', which I loved, because it was relatively long and with an action that didn't stop. That is why I later bought the entire game and was completely disappointed, nothing to do with the demo.
Sort of like watching a longer trailer for a movie, then realizing at the cinema that what you've seen in the trailer were the only interesting scenes in the entire movie.
The Will Rock demo is always there https://www.gamepressure.com/download.asp?ID=2758 ,