I wanted to buy the XCOM Enemy Unknown Pack (Update: sorry, the link is dead), but this was a major pain:

  1. Checkout and login both result in a HTTP 403 Forbidden error in the latest Firefox. Switched to Chromium.
  2. You have to register with the site before being able to buy anything.
  3. After registering, receiving the confirmation email, clicking the confirmation email link, logging in, re-adding the game to the basket, clicking "Checkout", ignoring their "Rewards" page, filling in the delivery address (it's a flipping Steam game!), ignoring their "Trade-in Info" page, filling in the payment info, clicking "Make Payment", and waiting for the "We are processing your order" page to redirect, I was sent back to the front page with no message of any kind. The payment was apparently not registered. Fffffffuuuuuu

At the second try the purchase went through, but damn!

And after a bunch of cutting and pasting the game is now active. I can see how buying Steam games from third parties is a lot more of a pain than the original shop.