Rules of the Game

A Videogame Trope where certain rules are put in place for a certain stage of the game. These rules will generally restrict the player's actions somehow or otherwise put the player at a disadvantage. Sometimes though, these rules will actually work to the player's advantage. If that happens, it's usually because random chance determines what kind of rules are put in place. Expect to see this trope if a battle occurs as part of a competition of some sort.

There will generally be one of two ways the rules are enforced:

One: It's simply impossible to break them. The game won't allow any attempt to do so. The Dark Cloud example below takes this form.

Two: The game will impose a penalty for violating the rules. The Shin Megami Tensei Nocturne example takes this form.

Examples of Rules of the Game include:

Occurs several times in the Final Fantasy series
- In Final Fantasy IV, the Lodestone Cavern paralyzes anyone wearing metal equipment until Gilbert / Edward breaks the spell between the first and second Dark Elf fights.
- In Final Fantasy V, the western half of the Fork Tower dungeon prevents the use of physical attacks (or, more precisely, monsters counter physical attacks by resetting the battle), while the eastern half prevents the use of magic.
- In Final Fantasy VI, physical attack commands are disabled in the Cultists' Tower. (AI-controlled party members, such as Umaro, or anyone with berserk status, can still attack normally.)
- In Final Fantasy VII, the Battle Square in Gold Saucer makes you spin a slot machine before the beginning of each new fight. The result of the slot machine will determine if any restrictions are in place for the battle. Some results are actually beneficial, such as restoring your health.
  - The harsher the penalty, the more the round is worth if you win. Conversely, helpful results offer very little value for the round. Many penalties could be circumvented with the right equipment/materia set-ups equipped in advance (like a Ribbon), assuming you didn't get your protection broken by a previous penalty.
  - Borderlands does a similar example in the Tunderdome arena. After every wave, an effect is imposed on the players to make the fighting challenging, such as enemies having faster shield regeneration, certain guns doing more damage, head shots being the only way to kill enemies, etc. The effects can go up to 3 at a time.
- In Final Fantasy VIII, most commands are initially disabled in the Very Definitely Final Dungeon; they can be unlocked again by defeating optional bosses.
Dark Cloud has floors called "Limited Zones" that place various restrictions on you, such as only allowing you to use one character or causes your weapons to lose experience when used rather than gaining it.
- Dark Cloud 2 brings this back with the sealed floors: Red forbids you from using Max, Blue forbids you from using Monica, and White forbids you from using any healing items. Thankfully, if you destroy all of the monsters on a sealed floor, the seal goes away. (Although, for some floors, this is easier said than done.)
In Shin Megami Tensei Nocturne, the Ahriman battle(assuming you aren't going the Shijima route) has two parts: In the first part, Ahriman challenges you to a game and imposes a different set of rules for each round of the fight. Any character who violates these rules is instantly killed. The second part is a straight up fight.
In Persona 4, Adachi has a floor in his dungeon where he forbids you to encounter any Shadows while making your way to the exit. If you do, he promptly kicks you out of the dungeon.
This is the whole point of Tower of Heaven.
The "Laws" in Final Fantasy Tactics Advance, complete with Judges who penalize you for breaking them.
This is half the gimmick of the Glitz Pit from Paper Mario: The Thousand-Year Door.
Kingdom Hearts II had the Underworld Colliseum tournaments, which would impose rules for each type of tournament, limiting what kind of moves you were allowed to use.
In Recettear sometimes special circumstances are applied to each level of a dungeon while you're exploring them. They can be helpful (e.g. doubling your attack or defence power or revealing the map, increasing your speed), neutral (e.g. supplying the aforementioned benefits to both you and the monsters) or negative (e.g. only applying benefits to monsters, disabling the map). The very last dungeon only applies negative effects and does so on every level.
In Nethack's Sokoban Bonus Dungeon boulders can't be pushed in any diagonal direction, you can't squeeze diagonally between two boulders which sit diagonally across from each other, and levitation won't prevent you from falling down through holes in the floor.
The Battle Arcade from Pokémon Diamond and Pearl Pokémon Platinum]] and HeartGold and SoulSilver is a textbook example.