Bosses and game mechanics

In a previous post I explained bosses often have a special appearance or atmosphere surrounding them in order to make the player understand the encounter moment is particular. The game mechanics part of a boss is as unique and special as its appearance: there is an extra-ordinary strategy to follow in order to win the fight, but the player keeps his/her ordinary abilities : run, jump, throw/shoot, smash, etc.

Taxonomy

According to en.allexperts.com, a boss can be:

Adjective	Description	Example
strong	more life, more damage, usually has a weakness revealed from time to time	Mushihime-sama: this boss
stylish	medium-sized but faster than the player, more skilled, nearly perfect, often the antagonist seen as a better protagonist	Final Fantasy VII: Sephiroth
giant	big, single weak point or simply a bigger version of a normal monster	Final Fantasy X: Sin
stealthy	hidden or invisible, need to be revealed	MGS: The Fear
final	the antagonist, the bad guy behind the plot, has at least several phases/battles	Mystic Quest: Dark King
mini boss	weaker than "normal" boss, special strategy which has to be learnt but can become common	Doom II: Hell Knight
non-antagonist	not a fight but rather a competition/challenge to win	Super Mario 64: racing versus Koopa the Quick
stalker	repeatedly seen in different stages of the game, getting stronger at each new encounter, troublemakers, the hero and him/her may become friends after the last encounter	Pokémon Red/Blue: Giovanni or the Rival
hidden	fought just before or just after the supposedly-final boss, needs a task to be done before, might sometimes be totally unbalanced so that the player keeps trying to finish the game	Golden Sun: Deadbeard
team	multiple normal or a bit better than normal monsters acting together, combos	Tales of Symphonia: Defense System, Zelda Ocarina of Time: Twinrova
puzzle	invulnerable unless a puzzle is solved; the puzzle grants the player a super weapon, lowers the boss' defense or traps the boss	God of War: Minotaur
tricky	can not be defeated with the current abilities, but a special item can be used to kill the boss instantly	Warcraft III: the Mannoroth blood fountain where Grom Hellscream drinks to kill Cenarius
timed	player-independent, wait for the boss to die or kill him before a certain time	Final Fantasy VII: Emerald Weapon
multistage	change depending on how heavily damaged	Wario Land II: Captain Syrup
unbeatable	invincible or way too powerful, it is written in the storyline that the player has to loose, the boss becomes defeatable later in the story	Baldur's Gate II: first encounter with Jon Irenicus
easy	after a hard lvl, surprise!	Incredible Hulk: The Leader

In practice

Bosses combine multiple of the aspects mentioned above (you can use the checkboxes to determine in which categories your favorite boss fit). In MGS for instance, Snake, the hero, can fake death to kill The Fear. The Fear is supposedly a stealth boss, but this secret way to kill him makes him a trick boss. Similarly, Ugh Zan III, the very last bost in Serious Sam, combines strength, a puzzle, a giant shape, multistage and it is the final boss (killing it ends the story). I find the Croteam studio has done a very good work on Ugh Zan III, whether about the plot leading to the boss encounter, the 3D design or the puzzle the player has to solve to kill it. This is worth a video :-)

A boss is an opportunity for the game designer to be creative and try new things. The innovation can sometimes be really appreciated by the plaers, and become new standards for boss startegies. For instance, in MGS, if the player does not wish to struggle through this battle [against The End], the player [...] can simply turn off the console and wait for seven days (or set the system clock a week ahead). This will result in a secret cutscene in which The End has died of old age (according to wikipedia about The End). Another boss in MGS, Psycho Mantis, breaks the fourth wall, according to destructoid:

Psycho Mantis begins showing off and bragging about his telekinetic powers.
First off, Psycho Mantis proceeds to read the actual memory card you have in your system. If you have played any other popular Konami game at the time (particularly Castlevania: Symphony of the Night) Psycho Mantis will remind you how much you like “Castlevania,” eventually even commenting on how much you have saved during the game.
After displaying this impressive (and pretty darn innovative) feat, he asks you, the actual player (!), to place your controller on the floor so he can show you how powerful he really is. Upon your abiding to the creepy video game boss’s wish, Psycho Mantis grabs his head and, using the built in rumble of the DualShock, has the controller shake uncontrollably, even, if you happen to have to set it on a high table, making it fly in the air and tumble to the ground below.
If that weren’t already enough, once the battle begins you realize that there is no way to beat Mantis. Since he can read minds, he manages to dodge every single attack you throw at him.
Through trial and error (and most likely a guide), you eventually figure out that, in order to beat him, you must unhook your controller from port #1 and attach it to port #2. Once this is accomplished, Psycho Mantis will actually comment how he can’t read your mind anymore.

Original

Chad Concelmo, the destructoid game critique for the encounter with Psycho Mantis, wonders why more game designers have not experimented with this innovative and ridiculously original gameplay technique. I think the reason is playing with the fourth wall might become dangerous as the player is not immersed in the game anymore. A boss should not be taken only as a punctual challenge to the player, it is also, as I explained a situation of narratic climax. The encounters with The End, The Fear or other Psycho Mantis in MGS are memorable (this word appears 8 times in Conselmo's article) because each of them is unique. These humans with super powers and weird physical particularities (The End was born in the early 1860s and can summon the spirits of the "holy forest" he waits in to revive his stamina through directed sunlight according to wikipedia, The Fear has a 20-cm long tongue, Psycho Mantis' has mental powers and a mask covering his horrible face) are beaten by Snake, a normal-looking soldier with exceptional capacities, not weird powers. Psycho Mantis predicting the player's moves seemed previously unfair, but the fight becomes more achievable when the player learns how to kill him. And when the boss is finally killed by the player, the first reaction is "I did it!". Thus, breaking the fourth wall seems to work fine if the aim is to make the player solve himself the puzzle boss he/she is fighting. It is like boxing in Wii sports: the fight occurs also outside of the game, and that immerses the player even more.

Breaking the fourth wall "the other side" could consist of a mise en abyme. In a PS3 game for instance, it could be funny to play the same or another console game. Beating the boss at this console game inside the PS3 game could be the only way to defeat him/her/it. You could think about playing GTA 2 versus Jimmy Pegorino in GTA IV. In all Pokémon games, the protagonist's bedroom contains a console (Nes, SNES, Game Cube, Wii) but I do not think the protagonist can use them to play actual games.

Don'ts

Repetitive bosses always following the same strategies in a game are boring. Creativity matters.

Players can cheat often in boss battles. For instance, in Mystic Quest, casting Heal on the Dark King deals ridiculous damage (more than 20K while the boss has 40K HP) on the boss, ending the fight in 2 or 3 turns. In Mega Man 1, when fighting against the Yellow Devil the player can exploit the Pause Button/Thunder Beam glitch. This glitch seems to be known from many players. use Pause with a special gun to shoot each time the game starts again. In repeating Pause/Start, the player can shoot without being shot. To my mind, this is a bad design (or a bug) that should have been addressed when conceiving the weapon behaviors.

You have to burn the rope is a concept-game in which the player only faces a boss. The strategy to kill it is obvious and reminded to the player. I think easy bosses should not appear too often, otherwise players get bored of the lack of challenge. Anyway, I wonder which percentage of players go directly to burn the rope, and which percentage try to kill it by other means (eg throwing axes or jumping above).