Payment processors like bitpay and coinbase make it easy for sites to implement Bitcoin as a payment system for their products. It would probably take minutes or hours to code this up as an option.
Edit - now I see you are handling the checkout through Fastspring. so maybe it would take hours or days to code 
Anyway Do others want to use BTC to buy games?
:-PLATO
I wouldnāt touch bitcoin with a 4ft pole if I was a user, let alone a merchant. Itās far too unstable to be used right now and relied upon as an actual currency, and even with processors which convert instantly to USD, itād cause the BTC price of the game to constantly fluctuate from anywhere between like 0.0233 and 0.1BTC in the past two weeks.
Oh, well then you would want to enable the āAuto convert to USDā option on Coinbase or Bitpay, and take my money (BTC) as USD in your bank account.
This actually is the problem. Bitcoins are not made for speculations or as an ātransport currencyā.
And the only way to get it more stable is to use and accept it like a fiat currency (USD, EUR,ā¦). If more merchants accept it then it become more reliable and the people would look at the BTC-prices of products instead of the exchange values, to rate the value of an BTC.
But every merchant have to decide for itself, if he want to accept Bitcoins.