

IMHO, two hours is not nearly enough to get a feel for a game. At least, not for the sorts of games I tend to play. I spend longer than that just working through initial technical issues, configuration, and (in games that have one) the character generator.
I have to conclude that Steam’s return window is either intended to be just enough to see if you can get it running, or as much as Valve could talk publishers into tolerating.
You are mistaken. Heroic simply uses an affiliate link to generate money for the project.