[This is a repost of a gameranting post]
I am not a great fan of boss fights. Nevertheless they are an integral part of the gaming experience. After many boss fights I came up with a simple rule to determine if a boss fight is acceptable and when it starts ruining the game. The rule is measured in the number of times a player dies in a boss fight.
First Death / trial: The player just encountered the boss and spends this trial, learning the attack pattern of the boss. Sometimes getting killed forms a part of this learning process.
Second Death / trial: The player has learned the attack pattern of the boss and must now formulate a counter-attack. Again the player might get killed because he has not perfected his counter-attack.
Third Death / trial: having learned the attack pattern and formulated his counter-attack, the player is ready to win the fight. Some players might experience even four or more deaths before beating the boss (or throwing the game in the dustbin)
The first and second death are acceptable deaths, the player is simply not ready for the challenge offered by the game. But from the third death onwards the boss fight steers the game on a sloped road, which leads inevitably to the dustbin.
There are games where the boss forms the ultimate challenge after finishing a level. I don't have any issues with those fights since their goal is to test the players skill. But this is not the case for games with elaborate stories where the boss is just another obstacle before viewing the next chapter. In those games players want to see the end of the story and if an unbeatable boss denies them that end, they will rightfully blame the game designer and not their lack of skill.