Rule 3 of RPGs — Some Players (Like Me) Won’t Ever Beat Some Fights
Observation Three: If a fight has any chance of beating the player, there is a percentage of users who will NEVER be able to beat it.
It took me a long, long time to realize this. Too long. But it is vitally important to understand the difficulty of doing game balance.
Everyone has bad days. Everyone has blind spots. Some people who reach your tough fight will have used up all their healing potions, or refuse to use the healing potions, or forget that they have healing potions, or never have realized that healing potions are potions you can drink that heal you. Because of this, whenever people reach a tough fight, there will be a few of them who just can’t beat it. They just can’t. You can adjust the percentage of people who lose, but it will never be zero.
(By the way, along these lines, if you put any puzzle or riddle in a game, there is a percentage of users who will never figure it out. This is why I’ve drastically reduced the number of puzzles in my games. Arguably, I have reduced it too much. It bears thinking about. However, this is my rationale for doing it.)
Source: Jeff Vogel, Three Rules for Difficulty in RPGs, The Bottom Feeder (Feb. 10, 2011).