Playtime can't be guaranteed, unless its a movie you have no control anyway. Its most likely just a suggestion. Did this game suggest a playtime that was vastly different to your experience?

Refunding a cheap (in price) indie game before the 2 hours play mark, AFTER finishing it is just a dick move. Also some games cannot be just measured by its playtime alone. Yes you can for yourself. But that would be like saying "oh I refund all 50 hours games, because I only consider a game to have a value over 60 hours playtime regardless its price".

Yeah, I'm using them as an example of an underwhelming product that nevertheless has a market at its price, which millions of people regularly purchase knowing how shit it is because the price is tolerable for a guilty pleasure.

Measuring the time in percentages here doesn't make sense. A 1 hour difference on a 3 hour game can easily be chalked up to variance (even the estimate of 3-4 hours has a 1 hour range) but 10 hours off a 30 hour game is enormous. If we also made it $50 instead of $5 and argued for time per dollar as a value metric, sure, those would be equally misleading, but time per dollar is less important as the total cost decreases. Nobody would say a 2 cent movie ticket is half as worthwhile as a 1 cent ticket. They're both approximately as valuable as the experience itself because the cost is negligible.