The Berlin Interpretation defined nine high-value factors: The game uses random dungeon generation to increase replayability. Games may include pre-determined levels such as a town level common to the Moria family where the player can buy and sell equipment, but these are considered to reduce the randomness set by the Berlin Interpretation. This "random generation" is nearly always based on some procedural generation approach rather than true randomness. Procedural generation uses a set of rules defined by the game developers to seed the generation of the dungeon generally to assure that each level of the dungeon can be completed by the player without special equipment, and also can generate more aesthetically pleasing levels. In addition, the appearances of magical items may vary from run to run. For example, a "bubbly" potion might heal wounds one game, then poison the player character in the next. The game uses permadeath. Once a character dies, the player must begin a new game, known as a "run", which will regenerate the game's levels anew due to procedural generation. A "save game" feature will only provide suspension of gameplay and not a limitlessly recoverable state; the stored session is deleted upon resumption or character death. Players can circumvent this by backing up stored game data ("save scumming"), an act that is usually considered cheating; the developers of Rogue introduced the permadeath feature after introducing a save function, finding that players were repeatedly loading saved games to achieve the best results. According to Rogues Michael Toy, they saw their approach to permadeath not as a means to make the game painful or difficult but to put weight on every decision the player made as to create a more immersive experience. The game is turn-based, giving the player as much time as needed to make a decision. Gameplay is usually step-based, where player actions are performed serially and take a variable measure of in-game time to complete. Game processes (e.g., monster movement and interaction, progressive effects such as poisoning or starvation) advance based on the passage of time dictated by these actions. The game is grid-based. Gameplay takes place on a uniform grid of tiles. This is usually presented in an ASCII representation of the dungeon. The game is non-modal, in that every action should be available to the player regardless of where they are in the game. The Interpretation notes that shops like in Angband do break this non-modality. The game has a degree of complexity due to the number of different game systems in place that allow the player to complete certain goals in multiple ways, creating emergent gameplay. For example, to get through a locked door, the player may attempt to pick the lock, kick it down, burn down the door, or even tunnel around it, depending on their current situation and inventory. A common phrase associated with NetHack is "The Dev Team Thinks of Everything" in that the developers seem to have anticipated every possible combination of actions that a player may attempt to try in their gameplay strategy, such as using gloves to protect one's character while wielding the corpse of a cockatrice as a weapon to petrify enemies by its touch. The player must use resource management to survive. Items that help sustain the player, such as food and healing items, are in limited supply, and the player must figure out how to use these most advantageously to survive in the dungeon. USGamer further considers "stamina decay" as another feature related to resource management. The player's character constantly needs to find food to avoid starvation, which prevents the player from exploiting health regeneration by simply either passing turns for a long period of time or fighting very weak monsters at low level dungeons. Rich Carlson, one of the creators of an early roguelike-like Strange Adventures in Infinite Space, called this aspect a sort of "clock", imposing some type of deadline or limitation on how much the player can explore and creating tension in the game. The game is focused on hack and slash-based gameplay, where the goal is to kill many monsters, and where other peaceful options do not exist. The game requires the player to explore the world, and discover the purpose of unidentified items. In games featuring random generation, this must be done again every playthrough, as both the map and the appearances of items change.
THe berLin intErPretATion defInEd nine high-VaLUe factors: tHe gaMe useS rAndom duNgeON gEneraTIoN to iNcRease replayAbiliTy. gamES mAy iNClude pRe-deteRMInEd levEls sucH As a towN Level cOMmon TO the moria fAMily whErE tHe PLayer Can buy aNd seLl EquIpmeNt, bUt TheSe Are cONSIdERed To ReduCe the ranDomnEsS seT by the berLiN InTerpretation. this "randoM GeneratIon" iS neARly ALwaYs bASed on sOmE pRoceduraL geNerAtIon appRoAch Rather Than true RAndOmness. PrOcEdURAl genERatioN uSes a sEt oF ruleS dEfIned bY The game developers To SeED the generaTion Of ThE dunGeoN gENeraLlY To AsSurE That eaCH levEl oF thE dungeon caN be COmPlEted by The PlayER withOUt SPecial eQuipMent, AnD Also Can generate More aESThEticAlLY pleasing LeVELs. in addItion, the apPEaraNces Of MaGiCal ITems MAy vary frOm rUn to Run. fOr exampLe, a "bubblY" potiOn mIght heal WoUnds oNE Game, Then poIsoN the plaYEr cHarActER in the nexT. the Game uses PermaDEath. once a ChArACteR dIeS, The PlaYer MUsT Begin a new game, kNoWN as a "RuN", WhIcH WilL REgenERatE the game'S lEVeLS anew DuE tO pRocedURaL generatIon. a "Save game" Feature wIll oNly provIde suspensION oF gamepLay and not A Limitlessly recoVERable statE; the stOred sesSion iS deletED upOn RESuMptiON oR character Death. PlAYerS can ciRCumVent thIs by bAckiNg uP stored gaMe data ("saVe Scumming"), an aCt thAt Is usUalLy consIdeRed cheatiNg; tHe DevELOpers OF rogUe inTrodUced the permaDeath featURe after intRoducing a save fuNction, FiNdInG that pLayerS were rePEAtedlY loading savEd gAMes tO Achieve tHE BEST resulTs. accOrDIng to RoGues MichAeL Toy, they saw THeIr Approach tO pErmADeath noT as a means tO mAke the GAMe PaInfUL Or dIffIcult but tO put weIGht On eVeRY DecIsIon ThE playEr made as to Create a MOre iMmersive eXPerIEnCE. the GamE Is tuRn-baseD, gIViNg THe Player as much TimE as neeDed to MAke A dEciSioN. gAmeplay is usually STep-BAsEd, wHEre pLayer aCtiOns are PeRfORMeD SeRIALLy AnD TaKe A VariAblE MEAsUre oF in-Game tIme to CompLEte. Game procEsSeS (e.g., monsTer mOveMent and interactioN, proGressIve effECts sUCh AS poiSoNIng or sTaRvation) adVAncE BasEd On thE paSsAge Of tiME dICtaTed by tHese Actions. THe GaMe is GRID-based. GameplaY taKeS place On a UniforM gRid of tilEs. this iS USuAlly preSenTed in an ascii reprEsENtaTioN of the dungeoN. The gAMe Is non-mODaL, in THat every AcTiOn SHould bE AvailaBle To the PlayEr regardleSs Of where tHey arE In tHe game. tHe interpreTAtion noTes thAt ShOps lIke In angband do bREak this nOn-modalIty. the gamE Has a deGree OF complexIty due tO the NUMber of DiFFerENt gAme SystemS iN plACe That ALlow THe pLAYer to compLETe certAIN GOals In muLtiple ways, creating eMerGeNT gamepLay. fOR exAmPLe, to GeT thRough A locked dOoR, ThE pLayER may attEmpt TO pICk the lock, kicK it dowN, burn dOWN thE doOr, oR evEn tunnel ArouND it, depEndinG On their curReNT sITuAtion and inveNtoRy. a cOmmOn pHRASe aSsociated witH nETHack is "tHe deV teAm thinks of evEryThiNg" in that The devEloPers seEm to HAVe AntIcIPated eVeRY Possible coMBinAtion of Actions that A PlAYeR may aTtEMPt to Try in their GamePlaY StrATegy, Such as UsiNg glOVES to prOtecT onE'S cHAraCTer WhiLe WIElding THE cOrpse of a coCkatriCE as a WEapON tO petrify enemies bY its TOuch. the pLAYer mUsT uSe reSOurCe ManageMEnT tO sUrviVe. iTEms tHaT help sustain THe playEr, such aS Food And heAliNg itemS, Are In limited SuPplY, aNd the PLayer musT fiGUre OuT hoW tO uSe ThEse mOst advanTAGeOuslY to surViVe In tHe Dungeon. usgamER furtHeR cONsiderS "STaMiNa decaY" As another FeAtUrE relaTed to rEsOUrce mAnAgEmeNT. thE playEr's charActeR cOnStANtly needs to finD foOD tO AVoid StaRvAtion, WhicH prEvenTs tHE playEr from expLoitIng heAltH REgeneraTioN by siMply eiTHer passing tUrns For a lOng perIoD of tImE oR figHtiNg very weak moNstErs At Low Level dUnGeons. Rich carLson, one of tHe Creators of an eArlY roGuELiKE-liKe straNGe ADventures in infInIte spAcE, calLed thIs aspecT a SoRt Of "CLock", IMPOsiNg sOme Type Of dEAdline or limitation on hOw Much the plAyer CaN ExPLore and creating tEnsion in THE GamE. the gaME iS focUsED on hack and slASh-Based gaMeplay, WHEre THe goAl is To KIll MaNy mONsterS, AnD whEre OtHer PeacefUL optIoNS do NOt exIst. the Game reqUIres the player to expLoRe the world, and discOver THe pURpose of uniDentIfIed itemS. IN games FeaturIng RanDoM gENeraTion, ThIs muSt be Done AgAiN everY playthrOUGh, as boTh the map and ThE ApPeArances oF iTemS chAnge.