Sure, you can try to discredit me because I just graduated from grad school this spring, but I have been making games for a while. To be honest I have never heard of Jeff Vogel before nor have I heard of Spiderweb Software, therefore I have not played any of his games. This is not an attack on him, he seems to be a successful indie game developer.

I realize he wrote a whole article, I did not read it all, just the bold stuff. This sort of idea about difficulty has been sprouting up since casual games hit the main stream a few years ago. Most people seem to think casual games got so popular because they are so easy, I totally disagree. That is what my comment was based on.

As for making the game "too easy" (notice I said "too easy") being the worst thing, how much fun is it to play an 8 year old in basketball? How fun is it to play chess against someone that has never played before? How many games have you been bored with because they are too easy. Making a game too easy is bad, it will just make players stop playing. The key is finding the balance between difficulty and skill (go ahead and graph it based on your playtesting surveys) and riding that curve up and to the right the entire way.

The reward can be independent of difficulty. The reward is juicy feedback. It is empowering. The problem is most people assume the reward must be something relevant to the game mechanics, like a bigger sword, but that is not true. The reason I used Peggle as an example is because user feedback basically has nothing to do with the actual game. The fireworks, soundtrack, bling-y graphics, all of that is what puts the game over the top. You think that the extravaganza that happens at the end of each level has any impact on the difficulty of the game? No, it just makes the player feel awesome. Sure, it is not as tough as Ikaruga, but have you tried the Master Levels? They are not easy. The feedback is not part of the difficulty.

As for the actual bold parts of that article:

"People will forgive a game for being too easy. They will never forgive it for being too hard." (I switched it since he disagrees with the opposite)

Eh, I guess. But there have been times when I have died while playing the game and I did not blame the game, I blamed my skill. It was not the game's fault. It is bad to make a game too difficult, just as bad as it is to make a game too easy.

"People will happily forgive a game for being too easy, because it makes them feel badass. If a game is too hard, they will get angry, ragequit, hold a grudge, and never buy your games again."

My whole argument is that you do not need to make the game easy to make the player feel badass. Even then, if the game is too easy players will think it is pedestrian and not play it.

"When a player is on the default difficult level, has built his or her characters poorly, and is playing straight through the main storyline with mediocre tactics, that player should almost never be killed."

I would think this is a problem with the tutorial or how complicated the game is. It should be straight forward to see progression of most players and know roughly at what point they would be at throughout the game. If they do not know how to play (have mediocre tactics) that is probably not a difficulty problem. I would look at what made the player think those choices were good, and then try to figure out how you can reinforce the right ones with juicy feedback.

TOO LONG DID NOT READ VERSION:
Your game might not be too difficult, it might just need more/better feedback for the user to make them feel awesome. If your game is too easy it will fail, probably the same way if it is too hard.