Steam states that you must not have played the game for more than 2 hours or you must not have had the game for more than 2 weeks in your library.
Steam is renowned game developer’s Valve’s Facebook for gamers. It’s a store hub with lots of social elements for its humungous supported game line up. From Indie start-ups to huge triple A developers like Bethesda, it’s got something for everyone. But, aye there was the rub, Steam never allowed refunds.
Gamers rejoice. Steam has had a change of heart as you may now ask for refunds via the Steam client and via Steam Help. If they allow it you will have the full amount reimbursed to your Steam Wallet. You may request for a refund from full games to downloadable content (DLC).
Steam states that you must not have played the game for more than 2 hours or you must not have had the game for more than 2 weeks in your library. So I believe reasons such as the game is awful would still be a valid ground under these conditions.
Steam is actually very late to the party in allowing refunds as competitors GOG and EA’s Origin allowed it way way back.