Many years ago -- this is ancient history on the OHR scale -- Haggard wrote a review of Sheep Rancher that included the following line:

This is one of the only OHR games that knows the difference between 'difficulty' and 'challenge'.

At the time, this sentence mystified me. I mean, I made the game, and I wasn't clear on the distinction. I had an okay idea of what he meant by it, but the difference had never really occurred to me. How can you make something that's challenging but not difficult?

Flash forward to a month ago. I'd just picked up Valkyrie Profile 2 the day before and cleared the first dungeon. I was really impressed by the elegance of the battle system: a careless player would be killed easily by the random encounters, but with some caution, you could avoid taking any damage at all in most battles. Browsing around at work, I stumbled on Gamespot's review of the game, where he called the game overly difficult, relying too much on levelbusting. I was incensed. From my experience, though it was pretty unforgiving, by no means was the game a levelbuster. It just asked for a little strategy beyond button-mashing. My mind immediately flashed to Haggard's review, which I'd given some thought to in the intervening years. This reviewer, I concluded, doesn't know the difference between difficulty and challenge.

This has become a bit of a debate on the forums lately. I had this article written already and was going to save it for next month, but today it's topical. Isn't that exciting?

Let's start with the dictionary definitions. According to Merriam-Webster, "difficult" means "hard to do" and "challenge" means "a stimulating task or problem." At a glance, these definitions leave something to be desired, but I'd like to focus on a single word: "stimulating," which is itself defined as "exciting to activity or growth or to greater activity." A challenging game is stimulating -- a challenge is something that provides an exciting stimulus that requires your precise response.

A necessary prerequisite to a challenge, then, is that your actions make a difference. Buying a winning lottery ticket is exceedingly difficult, but it's not challenging at all: you have no control over the outcome. Watching a movie is neither difficult nor challenging, since there's no way to fail.

So in the anatomy of our challenge skeleton, let's start out with an objective for the player. On a smaller scale, perhaps the objective is to win a battle or even just to survive. On a larger scale, we're challenging the player to beat the game. If the objective is the backbone of the challenge, then it's supported by legs: those are the obstacles that can prevent the player from achieving the goal. It's not necessary for these obstacles to punish the player with a "game over" -- there are plenty of challenging adventure games where the player can never die. What is necessary is that the player has control over his outcome when he faces an obstacle.

This is the key difference between a good challenge and artificial difficulty. Suppose you add an enemy to your RPG that only has a 1 in 255 chance of appearing, but if it ever does, it instantly kills the player's entire party. That makes the game more difficult -- that is, harder to do -- but the only thing it stimulates is the reset button. A better idea might be a timer that counts down to game over. It is within the player's power to avoid losing the game. (Disclaimer: That's still a pretty bad example.)

Or, bringing it back to my earlier example, Valkyrie Profile 2's battle system. You're given freedom to move around the battlefield and you can see the enemies' area of attack, so it's possible to avoid damage in most cases -- but very difficult. Mario & Luigi: Superstar Saga also featured a battle system that allowed skilled players to avoid taking any damage at all. Both games had stimulating, challenging battles. Valkyrie Profile 2 is the more difficult game by far, though, since it punishes your failures much more severely.

Is difficulty a bad thing? No. I hope I haven't obscured that in the preceding paragraphs. Difficulty can be wonderful. However, it's not a replacement for challenge. Challenge is a core concept in gameplay: the player's actions must make a difference. A player who does well should be rewarded and a player who does poorly should be punished. Superstar Saga is an easy game, but because it's also challenging, it's a lot of fun.

Suppose your game is open-ended; there are a lot of possible outcomes, neither one inherently better or worse than another. Is challenge still relevant to your game? Yes. Consider the Civilization series. Is a military victory better than a diplomatic victory? The game doesn't presume to tell you which way to play, but there are different challenges associated with each path.

In conclusion, challenge is a necessary element to any game. Not just RPGs, not just video games -- it is a universal concept in game design. Understanding challenge is a necessary prerequisite to becoming a great game designer.