Video game history is littered with examples of DLC so unbelievably poor that it’s surprising charges weren’t brought against the creators. But if you thought Oblivion’s functionless $2.50 horse armor and the $3 it cost to see nipples in The Saboteur was bad, have a look at what is possibly the most jaw-dropping piece of downloadable content ever: a $35 certificate.

The game in question is an old-school text adventure called Hadean Lands. Like so many of those classic titles from yesteryear, there are no graphics in the game; you simply type in commands and read the story of an apprentice alchemist stranded on an alien planet.

As you can imagine, the game is pretty hard, and it’s this difficulty that led to developer Andrew Plotkin adding the unique piece of DLC to Steam. Your $35 gets you a file containing a printable PDF or JPEG certificate, which states that you pledge to complete the game without using walkthroughs or referring to any hints.

In Plotkin’s defense, he has said that the DLC is to be taken lightheartedly. Speaking to Kotaku, he added that a higher price was a good way of keeping people invested, but he wanted to make paying more for Hadean Lands optional.

Speaking from a player's point of view, he said: “If this was a $5 game I’d just close the game window, but after paying $30 I want to kick its butt.”

I wanted a way for players to buy into Hadean Lands at that level of investment. Again, I didn’t think I could *require* it. But as an optional challenge, which a player could opt into? No reward except for a nice certificate and the knowledge that they’d made the choice? Sure. That makes sense. And: It’s funny. I mean, I think it’s funny. I don’t want to kick the joke to death, but people seem generally to take it in good humor.

Whatever Plotkin’s reasons for the DLC, it certainly draws attention to his game. And it should come as little surprise to learn that he’s already sold at least one of the certificates so far.