Easiest way is have two steps:
1. Have a demo of the game available so people can try before they buy and see if it actually works, isn't full of bugs, etc. I demo'd Batman and loved it so bought it. I demo'd Arma 2 and could see it had bugs but enjoyed it so bought it as I was expecting it. There wasn't a demo of OFP 2 and I bought it and regret it as I bought into the hype. Luckily I saw the thread on here so took it back before opening it and was awaiting Modern Warfare 2 before seeing the thread on here agian so have cancelled the pre-order. I could have ended up buying it without knowing it lacked dedicated servers which is important to me. If I had opened it I would be stuck with it.
2. The store has to offer a refund if it is full of bugs, doesn't work properly, etc just like any other item in the consumer world. If you bought an electrical item and it kept switching off you wouldn't be expected to keep it because you opened it. If it turned out to be awful you have the right to return it as unfit for purpose.
I've given up buying a lot of PC games due to the fact a lot of them turn out to be bad and you are forced to sit back and take it on the chin. At £25 a go or so it is out of order.
When it came to Spore, however, it was so horrifically bad I returned it to the shop and refused to go until they refunded the item as it was utterly awful and nowhere near worth £35.
Basically consumer rights for PC games need to exist like they do for console games. YES people can pirate PC games, but it is still a minority and with torrents so freely available I think the days of walking into a shop, buying the game, going home and copying it then returning to the shop for a refund are in the past. It is a lot easier to download fully cracked if people are that way inclined. Not everyone who uses a PC is a pirate so why don't we have the same consumer rights as console users with regards to returns of crap, buggy games
