Turn-based movement. That cyclops that's standing there, arm raised to squash you with a thrown boulder? She'll stay like that, not attacking, not doing a thing, for a minute, an hour, even a year, waiting for you to press a key and make your move. This gives you time to plan, check your inventory, bite your nails over your empty inventory, crap yourself, attack, run away, et cetera. (Yes, it is usually done in that order.)
Extensive customization. The different races and classes, the sheer variety of equipment you can find, and the ways that you can use them.
Unusually for roguelikes, ADOM features a fair amount of story in the form of a manual and a detailed world to explore. The game takes place in the world of Ancardia, which is being invaded from another dimension by beings known as the Forces of Chaos. Their inherent wrongess have a corrupting effect on the world, turning people and animals into monsters, screwing up the weather, etc. A sage named Khelavaster has discovered that the source of Chaos' invasion of Ancardia is in a remote mountain range, the Drakalor Chain. Determined to stop The End of the World as We Know It, he went there to stop the invasion and never came back, followed by hundreds of other wannabe heroes. The player is one of them.A major feature is The Corruption, which grants the player various mutations that can be either beneficial or downright harmful. Another feature setting it apart from other roguelikes is the Karma Meter, which determines several NPC's reactions and which of the Multiple Endings are available.Find it here. A sequel called ADOM II: Legends of Ancardia has been released, and can be found Here, but it's still a work in progress. In addition, a crowd-funded campaign to give more updates to ADOM I was very successful so it will be receiving updates in the near future, and eventually a release on Steam.Fulfills theWiki Rule.
Acronym and Abbreviation Overload: The guidebook has all kinds of abbreviations that make it downright illegible unless you read the compiled list of acronyms and abbreviations. The lists of characteristics for the various pieces of equipment in the appendices are detailed only in shorthand.
Action Bomb: All the flavours of vortices attack by exploding into a massive ball of acid/fire/etc the turn after they stand next to you. This is as unhealthy as it sounds. They can't explode in the dark in 1.1.1.
Amazing Technicolor Battlefield: The Chaos dimension. along with the top level of the Tower of Eternal Flames, level 66 of the Infinite Dungeon and bottom of the Scintillating Cave.
Archer Archetype: The Archer class. Their phenomenal ability with arrows and stealth allows them to routinely decimate enemy hordes from a position of safety, while the rest of their abilities (such as melee combat and magic use) are fairly good, making for one of the most powerful classes in the game.
Armor-Piercing Attack: There is a weapon called a phase dagger that completely ignores the armour of the target. The downside is that on each hit, the game throws at you a message about you easily cutting through the armour, which requires you to press [more] much more often. And the dagger itself doesn't do much damage anyway, making it useful only against heavily armored mooks.
Also, any missile with the "penetrating" prefix or weapon with the "of penetration" suffix. Hur hur hur.
Artifact of Doom: The Chaos Orbs contain powerful magic, but the player is corrupted upon using. There are many other artifacts that qualify; some literally "doom" the player, some corrupt the player merely by carrying them around, some do both and curse themselves on equipping to make it as hard as possible to get rid of them.
Artifact Title: Averted. When it initially had only one dungeon, ADOM stood for Advanced Dungeons of Mystery, and a couple of versions later for AncientDungeons of Mystery. In version 0.9.0, where the overworld was implemented, the title was changed to the current AncientDomainsof Mystery.
Artificial Gill: Several items, most commonly helmets of water breathing and the autocursing ring of the fish (although you need two unless you bless one). As of version 1.2.0, also provided by a corruption.
Awesome, but Impractical: Quite a few class powers sound powerful but are really nerfed by other costs. For instance, the monk's level 6 power is a circular kick, but kicking is among some of the weaker attacks in the game and the power costs 2500 energy points to use. In other words, anything you don't manage to kill with the attack gets at least 2-3 free hits on you.
The Wish spell also counts, due to it taking so long to cast learn and cast that the PC will often starve to death in the attempt. Said spell normally takes at least 3000PP to cast — even level 50 wizards can't cast it without grinding stats and flat-out abusing the game mechanics. Oh, and casting it drains a random stat by 10. One Self-Imposed Challenge is to raise a character that can cast it at will.
Moloch armor gives a massive bonus to your PV as well as fire immunity, but it weighs so much that most players won't even be able to lift it without Strength of Atlas or some other extreme strength boost. In addition, it massively cuts your DV, Dexterity, and speed, meaning that pretty much anything with penetrating attacks can cut you to ribbons.
Several non-corruption character traits are also double-edged - randomly teleporting is overrated, and even invisibility has its (minor) downsides.
Body Horror: The protagonist gets ~18 corruption stages, while NPCs transform into hideous chaos mutants without warning.
Bonus Boss: Several, as with the optional dungeons. Also note that while not every powerful NPC is hostile, everyone is (theoretically) killable.
Bonus Dungeon: Quite a few of them. There are several that you are required to visit for special endings, but are otherwise optional and present goodies. Always-optional dungeons include the Gremlin Cave, the Pyramid, and the Minotaur Maze.
Boring, but Practical: The Farmer doesn't have the cool powers of the other classes, but carrying more stuff, needing to eat less, picking better herbs, gaining marks in polearms (the most balanced weapon class) faster than anyone else and making their own rations are all useful.
The Monk's class powers tend towards this. Reduced movement energy cost, the ability to smash walls by kicking them, and the ability to swap positions with any monster instantly aren't flashy, but are extraordinarily useful.
Emperor liches cast various nasty spells, including Death Ray and confusion, summon loads of monsters as meat shields, are immune to most mindcraft powers due to being undead, see invisible and have a paralyzing touch.
Great Wyrms are ancient really powerful dragons. They can cast spells unlike lesser dragons, and are immune to their respective element (ice, acid, lighting or cold). Special mention goes to Great Karmic Wyrms, which are immune to all four elements, making most magic useless against them. Plus, they are karmic beings, meaning that hitting them in melee makes the player unluckier with each hit.
Doppleganger kings have identical speed and defense power to your character, making them hard to hit and run away from, and do about ten times as much damage as you.
Bragging Rights Reward: True Strength, the best artifact girdle in the game, can only be gotten by reaching the fiftieth level of the main dungeon without ever committing an unlawful act. Not only is this ridiculously hard for normal endings and nigh-impossible for the others, but it's past a Point of No Return so you can't use it for anything else, and chances are that if you've made it this far, you're ready for the horrors of D:50. Also, if you commit a chaotic act while wearing the girdle, it will squeeze you to death.
Broken Record: The magic missile bounces! You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! The magic missile bounces! more... You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! The magic missile bounces! You are hit by the magic missile! You die...
The first one, the Pyramid, is only accessible to characters between levels 13 and 16, and sees you trying to defeat the mummy lord Rehetep for his ankh and wrappings. By ADOM standards, it's fairly tame.
The Bug-Infested Temple is a big step up from the Pyramid. It's packed with Lightning Bruiser greater claw bugs and killer bugs, both of which are tremendously fast, always punch through armor, and dish out huge numbers of attacks per turn.
The Minotaur Maze is a seven-level maze complex packed with traps, false walls, extremely powerful minotaurs, and false levels. Most players skip it, as it's unusually challenging even by ADOM standards.
Finally, there's the Quickling Tree. It requires two specific corruptions to enter and puts an extremely harsh weight limit on your inventory. Very few people ever bother with it, as the main reward is the Boots of Great Speed, an artifact that gives you a massive speed boost, but also dooms, curses, and corrupts.
The Cameo: You can meet Hawkslayer from Bard's Tale IIIand recruit him as your companion if your PC knows the secret password.
Cast from Hit Points: Not a good idea unless your life is on the line, because it abuses your permanent stats (resulting in potential stat drain). Necessary for an archmage, however.
Chest Monster: The perennial mimic. Annoyingly, for whatever reason there tends to be one in the shop on the Dwarven City level of the Caverns of Chaos — many player characters have died in what one would normally believe to be a safe zone.
Clingy Costume: Any cursed item that is wielded/worn. This is why scrolls of uncursing and holy water are precious.
And woe to the player who finds "trapped" armor, which uncursing will not remove...
Convection Schmonvection: Averted by the Tower of Eternal Flames; a low-level PC who wanders in unwittingly is liable to be rapidly cooked by the extreme temperatures.
The Corruption: The encroaching Chaos is warping and corrupting the creatures in the lower levels of the dungeons. As the Player Character dives into them, it starts to affect them too, manifesting as "Corruptions". Some of the corruptions make the game more difficult, some are useful, and having too many results in a rather nastydeath.
Cryptic Conversation: Yggaz the Fool and the Mad Minstrel do this. Also the fortune cookies, which may or may not be flat-out lying to you. (Also, many quest hints you get in conversation are pretty cryptic too.)
One of the most useful spells is Magic Missile. It's very cheap to cast, spellbooks for it are very common, it can kill many enemies at once, its range increases when trained, and it bounces off walls (so you can kill monsters in positions that other spells and throwable weapons can't reach). However, it's common for a player to make a typo and cast the spell towards a wall at a 180 angle in a narrow corridor. The spell will then hit the player and bounce off the opposite wall, hit the player again and bounce off the first wall again... Essentially, the spell will bounce and rebounce, always hitting the player inbetween, until it has reached its maximum range - at this point the character is usually dead. He's forced to watch a long cycle of messages about the Magic Missile rebouncing and hitting him, his HP steadily sinking, unable to do anything about it.
Similarly, getting paralyzed by a monster results in an endless series of messages of the monster hitting you, and the player can't control his character. On the other hand paralyzation is much less likely to result in death if the character is strong.
Damn You, Muscle Memory: One horrible example within the game itself: saving the game and quitting the game are "shift+s" and "shift+q" respectively, and have the same "y/n" prompt after. Late at night, when cognitive functions take a backseat, players may lose very promising characters for no reason other than their own carelessness. Which is really no different from anything else in the game.
Degraded Boss: Played with. The skeletal king guarding an item in the Tomb of the High Kings is actually also a rare monster spawn. It only appears randomly late in the game though, so the player is likely to see the guaranteed boss one first.
The Dev Team Thinks of Everything: You can use a whip in the tool slot to self-flagellate for a small Lawful alignment shift (at the cost of minor injury). Stethoscopes can reveal the basic stats of an NPC.
These are just a fraction of the sheer prevalence of this trope. If you played the game for years and think you have seen and thought of everything, you are wrong.
Can't resist one example: most players risk being bitten by swarms of tiny spiders if they are trapped in a giant spiderweb. If you're a Dark Elf, however, "You welcome your spidery friends."
His level adjusts to that of the PC, but as higher level PCs are generally better equipped and have more HP, one will have an easier time at level 12 than level 8.
Early-Installment Weirdness: Version 0.2.0 is fascinating to play. There is no overworld, only the main dungeon exists, there are no colours, and the way rooms and corridors are drawn resembles NetHack.
Easter Egg: Press '&' to open the monster memory, and type in "Thomas Biskup".
Eldritch Abomination: The Chaos creatures that are invading Ancardia. These range from living blobs of pure Chaos and corrupted animals to big powerful demons like the Orb Guardians and Balors. Shifting features, reality distortion and Body Horror are commonly mentioned in their descriptions.
Elemental Punch: The Burning Hands spell (Baptism of Fire for religious classes) is essentially a fire-elemental melee attack... that never misses. It also gets stronger and slightly cheaper to cast as you use it.
Inverted by the Insight spell, as well as potions of insight, which reveals hidden information about the player character. This actually makes sense because the player can gain new abilities from various sources, such as corpses, pools and items, without knowing it.
Enemy Summoner: Quite a lot, with the summoned things sometimes being able to summon as well.
"Suddenly a stone block falls on your head. You die."
Only an early-game killer. Even a mildly experienced PC usually has too many hitpoints (at full health) to be instantly killed by these traps - though they may leave you very low on hitpoints in the middle of a dungeon filled with monsters.
You can be killed by "trying too hard to become a great writer" (using a magical writing set).
In the same manner, doing alchemy wrong will kill you (and doing it right will still probably kill you), even with completely mundane ingredients, such as mixing as a potion of orange juice with a potion of water (or two potions of water), resulting in a vast explosion.
When walking around the wilderness, rain can rust your equipment and drench any scrolls or spellbooks you own. It'll even make you sick if you don't have a hood/hooded cloak.
Even the date you're playing the game on can be lethal.
Evil Sorcerer: Keethrax, the black druid; Nonnak, the master necromancer; Yulgash, the Master Summoner; Nuurag Vaarn, the Chaos Archmage. Plus all the dark sages and lich variants running around. Be very afraid.
YOU can also be an Evil Sorcerer if you want. If you really want to be evil, you can kick the cute puppy to death and then laugh at the girl who just wants her dog back. And then fry everyone in the village with lightning bolts.
Explosive Breeder: Worms of any kind and jellies should be killed before they have the chance to multiply. Kill them all. Kill. Kill. Sorry, flashback.
There are also gremlins, which are not that dangerous but which spawn explosively when they (or their furballs) touch water (naturally, there is a cave of them filled with water traps). Battle bunnies, which, while appearing only on one level of one dungeon, spawn faster than anything else in the game and are immune to scrolls of vermin control, which ordinarily neuter any spawners on the level. Thank the various gods for the rabbit knife.
don't have a fluff ball on your person when you go swimming.
Extremely Dusty Home: The Dusty Dungeon Level (DDL) and the level below it, Very Dusty Dungeon Level (VDDL). They are pretty much Informed Attribute however, as the description doesn't affect gameplay.
Extreme Omnivore: By the end of the game, your PC will have munched his way through half of Ancardia's human, humanoid and animal population for the various resistances, the stat boosts, or just because they were hungry. Usually raw corpses, if they don't have the Cooking skill.
You can even eat your own clone (in the form of a doppelganger), if you're hungry enough. *burp*
Fallen Hero: The Ultimate Chaos God ending requires you to be Lawful or Neutral, to get the Trident of the Red Rooster, but to finish the game with fully Chaotic alignment.
Fan Nickname: Thomas Biskup, the author, is almost universally called The Creator in the fandom.
The little girl's pet dog is almost always referred to as "Kenny".
A certain ancient wyrm, depicted by the purple letter W, sometimes referred to as "Barney".
Final Death: "Do you want to [g] generate a new character?" ...*sigh* Yes.
Five Races: Averted. Stock humans, dwarves, orcs and hurthlings, but there are also gnomes, three flavours of elves and the ability to play as a drakeling or a troll. They all have unique specialities, and playing Drakelings and Trolls in particular present significant gameplay differences.
Drakelings are great. Having the racial ability to spit acid at the cost of satiation can be a lifesaver.
The other fun thing about the reptilian Drakelings is that when they're exposed to fire, their speed goes up.
On the other hand, Drakelings can never become completely immune to fire. The mandatory trip to a flaming tower still causes injury from your severely overclocked metabolism, even with equipment that would make other races immune. Too much of a good thing, indeed. Also, the flip side of speeding up when things get hot: Drakelings do indeed slow down when exposed to cold.
From Bad to Worse: The first three levels of the Tower of Eternal Flames are hard enough, what with the constant fire damage, melting equipment, and monsters that are hard to take out in melee. You thought THAT was bad? The fourth level is hotter, blocks teleportation, and requires you to dig through a lot of solid wall to reach a horde of resilient fire elementals and demons, and THEN you can fight the boss, who sees through invisibility and uses corrupting attacks, confusion, stat drain, high-intensity beam attacks, and has huge hitpoints and melee damage output.
Full-Frontal Assault: True berserk, a slightly hidden game mechanic. Not wearing any armor (except of rage) while berserk damage and hit chance even further! It also removes the warning about accidentally attacking friendlies.
Game-Favored Gender: Arguably females have an advantage in ADOM for a few reasons such as having access to an extra Side Quest, receiving cheaper keys from a certain merchant and in general having an easier time with stores due to relying on Appearance instead of Charisma for shop prices; Gray Elves for example start with a Charisma score of 8 and Appearance of 18 and increasing Charisma is far more difficult overall. That said, males do have an extra option to deal with the very lethal Banshee and unlike females the massive Appearance penalties caused by most corruptions doesn't affect them.
A God Is You: If you dare, if you've solved all the (optional) puzzles to gain the right equipment, and if your character is sufficiently badass.
Grimy Water: Do NOT swim in the red water — and beware of confusion that could make you stumble into it. Learning how to get across it is just one of the many mini-puzzles the game presents you with.
Guide Dang It: If you aren't spoiled, it's twice as rewarding and three times as frustrating. This also applies to nearly all of the side quests; read the ADOM Guidebook's appendix on them for the sake of your blood pressure.
One example: do you remember the first monster you killed? No? No Ultra Ending for you, then!note That particular key doesn't disappear, so it can be found by brute-force searching if you're thorough.
And figuring out what to do with a certain dying sage...
Healing Factor: PCs born in the month of Candle already inherently heal faster than Healing at 100 would let you. Trolls heal the fastest of all races. Being a healer has self-explanatory benefits. What happens when you roll up a Candle-born Trollish Healer? Near Wolverine-classHealing Factor! Especially since healers double, then triple their HP recovery at level 6 and 12.
Not enough? Start collecting items. You can wear a crown of regeneration, the artifact amulet Preserver, bracers of regeneration, two rings of regeneration on your hands and one in the missile slot and wield two knives of endurance. That's eight HP healed 'per turn' through items alone.
Still not enough? One of the corruptions grants another layer of Healing Factor. Don't forget to actually kill your enemies though.
Heavily Armored Mook: Some of the monsters have so high armor that they can be barely scratched with normal attacks.
Hell Gate: The Chaos Gate, which allows the forces of chaos to invade Ancardia. Closing it is the main goal for most player characters.
Hoist by His Own Petard: Shooting a Magic Missile in a narrow corridor? Bad idea. Chances are, a typo makes you cast it straight at the wall, so it constantly rebounds at you and hits you again and again and again until you're dead.
Implacable Man: There is an Eternal Guardian guarding a staircase somewhere in the middle of the main dungeon, preventing progress until completing a certain task. If you try to lure him from the stairs by attacking him, or even manage to kill him, an even stronger version of him will instantly materialise on the stairs. Screw up and you have multiple copies fighting against you.
The Rune-Covered Trident has good damage stats, comes with several useful intrinsics, and returns when thrown. The only downside is that unless you have a specific birthsign, you won't get it until level 36.
The Axe of the Minotaur Emperor is the most powerful weapon in the game, outdamaging even the mighty Trident of the Red Rooster. On the downside, it's incredibly heavy and tends to induce nasty defensive penalties.
Infinity+1 Element: Magic Missile can be useful in ways that the elemental bolt spells aren't. It's cheap to use. There is no elemental immunity to it. It doesn't destroy loot that has been dropped on the ground. It bounces off walls, letting you shoot people around corners. It won't make you unlucky if you attack a nonhostile or Karmic enemy.
Acid. Nothing is weak to acid, but very few things resist/are immune to it, and acid spells have the highest damage.
Infinity+1 Sword: The Trident of the Red Rooster is probably the best artifact in the game. It's also required for one of the ultra endings and is a huge Guide Dang It.
In-Universe Game Clock: Time runs far faster when you travel in the overworld because it's a zoomed-out representation of a large area. (And you do need to keep track of the time or date for several quests: ctrl-E tells you how much time has (E)lapsed since you first set out. Though it's easier to use Alt-q or "@" to check character details.)
Item Crafting: You can make your own crossbow bolts or arrows, and improve metal armour and weapons, with the right skills and the raw materials.
Joke Character: The Chaos Knight. You start out corrupted, most NPCs range from unhelpful to hostile whenever you play to type (forcing you to murder your way past most of the quests), and if you convert from Chaos to another alignment, you lose all class powers and suffer from a burning gut until you die or fall back to Chaos. To drive the point home, you can't get a normal ending either, unless you're redeemed; if you close the ChAoS Gate, you're immediately zorched for being a moron. If you are redeemed, you still perish, but at least it's a Heroic Sacrifice.
Merchants count as well; while they don't have the unique disadvantages of Chaos Knights, they also don't have their great starting equipment, stats, or class powers. Merchants start out dismally underpowered, with lousy equipment and class powers focused mostly around non-combat use.
Joke Item: The si — an artifact that multiplies, and cannot be gotten rid of easily.
Actually it may be considered a lethal joke item, as you have a supply of renewable projectiles as well as sacrifice fodder for your god. Even more mundanely, the sis make excellent Vendor Trash. The "you can't get rid of it" applies to an area that you can never return to (e.g. the Infinite level dungeon which generates a different level each time you move up or down a floor).
And then there's the Scroll of Literacy Check. "If you can read this, you must be pretty good!" (If your Literacy skill is not above 90, it'll read "f u ...")
The Black Tome of Alsophocus can let you learn any spell in the game; pro. You can't pick, and you're locked in place while you read it; con. There's a chance you can learn a big spell like Death Ray; pro. It corrupts you when used OR carried; con. Most players leave it where it is, or use it as fodder in the main quest.
The Boots of Great Speed give you a whopping +100 speed boost. That's the only good thing about them; they curse and doom you when you put them on, and wearing or even carrying them corrupts you rapidly. Being located at the end of the Quickling Tree doesn't help them at all.
Karma Meter: This is how the Character Alignment works, essentially removing the "does/doesn't play by rules" axes on the graph. Some quests can only be accepted if you're Lawful/Chaotic.
Killing even a single feline of any type makes an enemy of a powerful NPC, causing many to refer to them as "those damn cats."
Karmic Death: Don't eat the corpses of cute little helpless things (eg dwarven children, the tiny girl's puppy). Also, think very hard about attacking obviously good (Lawful) people. Some of them are very, very good at defending themselves. Or have extremely nasty friends who will kick your ass.
Kleptomaniac Hero: Almost anything can be useful, so it makes sense to pick up different things. Even a "scroll of cure blindness" (which can be turned into a blank scroll by dipping it in water) or a "potion of uselessness" (which can be thrown to propel yourself on the icy level of the Caverns of Chaos, resulting in an impressed deity giving you an artifact.)
Last Chance Hit Point: While ADOM generally doesn't care a whole lot about mercy, depending on your luck and mana stat you may occasionally find yourself surviving an overwhelmingly lethal blow with a single hit point.
Lethal Joke Character: Bards don't have a set skill sheet - every time you roll up a bard, they get a random selection of skills. If you have the patience to roll and re-roll a Bard, you can create a fantastic set of skills. Combine that with excellent class powers and a great Heir gift, and you have a potentially devastating class.
Lethal Joke Item: The potion of Uselessness. Really. If you apply the rules for Conservation of Momentum near the end of the game, the gods reward you with a free artifact for your cleverness.
Level Grinding: There are useful benefits to gaining a level. You're still not safe (you're NEVER safe), but you're less likely to die without warning. The game tries to avert this by refusing to give experience for killing more than a certain number of a creature, and by making creatures more powerful the more of them you kill. And just don't go to the small dungeon near the start at more than a few levels, because it gets harder as you get tougher, except much faster. (Although with enough resources at a sufficiently high level, particularly the ability to teleport when and where you like, it can become bearable again to at least run through.)
Level Scaling: The more of a single creature you kill the more powerful that type of creature gets. Gets fun when dealing with enemy summoners.
Linear Warriors, Quadratic Wizards: Played straight, but... Since any spells you learn are completely dependent upon you finding their (very fragile) spell books, a wizard may be forced to become a Magic Knight. Yes, a wizard with a few elemental bolt spells will be able to fry legions of Mooks with one hand tied behind his back, but he'd do better to save those spells and use the mooks for training his weapon skill in anticipation of an artifact. Elementalists are similar in that a lot of later monsters are immune to fire and ice.
Lost Forever: Oh so much. Put off entering the Pyramid or the Minotaur Maze until you have better gear? Oops, they close up once you reach a certain level. Talked to a certain NPC who immediately died? No Ultra Ending for you!
An even crueler example resides at the end of a particularly painful sidequest. After you defeat a nasty Bonus Boss, you get a unique scroll to take to a NPC to get the Infinity+1 Sword. The scroll can be destroyed like any other inventory item. If you read it, you can use a rare item to rewrite it. If you didn't...goodbye Ultra Ending.
Luck-Based Mission: Drinking from pools. You might get wishes or good intrinsics like death ray resistance or teleport control, or you might just get cursed, doomed, or sprayed with water and snakes.
MacGuffin Guardian: Sometimes there's a random artifact guarded by a tougher-than-normal named monster in an otherwise completely normal level.
Magic Knight: Any magic-using class will eventually have to start doing this but the Paladin, with their good weapon skills and decent casting abilities, especially excels at this.
Magikarp Power: Monks gain the (undocumented) power to kick down walls at level 13. Not that useful in combat, but there's plenty of uses for a never-breaking, no-weight intrinsic pickaxe, including making smithing more practical.
Make a Wish: Can be attained through rings of djinni summoning, magical pools or wands of wishing. You can wish for any non-unique item or monster, or even for abstract things like friends and wealth.
Metal Slime: Giant boars, oy. Required for the ultra endings, sadly.
The Minion Master: This is the hat of necromancers; bards can be played like this too, although having too many followers at once may result in them jealously attacking one another.
Min-Maxing: Apart from the Troll healer above, there are few moderately game-breaking min-max builds. Some race/class combinations do give you advantages because their abilities and stats stack, but it's less "OMG cheat" and more "give your PC the best start". Besides, stats are usually assigned randomly or semi-randomly.
Having said that, gnome or hurthling classes with high mana are likely to start with enough talents to acquire Treasure Hunter (increases amount of equipment randomly dropped) at level 1.
There is more than one way to start with three or more talents. The maximum number is six talents, for which you have to be a hurthling or gnome farmer, bard or merchant with 17+ Mana, Candle or Falcon as starsign, and some completely unrelated luck (you get a bonus talent if the sum total of your stats is divisible by 7). This would allow you to get Treasure Hunter and the truly game-breaking seven-league boots, at level 1. Yet - while gunning for extra talents is one aspect of min-maxing, it rarely does more than make the start a little bit easier. Also, while in this particular case you maxed the crap out of your running speed, you sadly happened to min your combat prowess.
Troll barbarians will have massive strength and toughness, but will be illiterate, ugly, clumsy, and dumb as a post.
Here is a list of all monster descriptions in the game.
Multiple Endings: There are many ways to win — some have a better outcome than others.
Even the regular ending has quite a few variations depending on your alignment and amount of corruptions.
Nintendo Hard: In NetHack, there's an endless debate over being able to identify items by their unique weight because it makes the game easier. In ADOM it's an almost necessary survival tactic. Unfair Game Breaker debates start at far worse.
No Fair Cheating: By all means, try and change something in a saved game via hex editing. All enemies will suddenly max out in levels, and your equipment will randomly disappear for the rest of the game; which is not going to be very long.
There's more than one way to skin a cat; at least up until the latest version. Instead of the saved game, modify the temp files.
Or go obtain a value editor and mod the game as you play it.
Non Standard Skill Learning: The game is unique in regards to this trope. You only improve your existing skills by levelling up and the usual way to learn new ones is from NPCs and wishes. However, mindcrafters and elementalists learn new Mindcrafting powers and new spells, respectively, upon level up.
Noob Cave: Played straight with the Village Dungeon and Druid Dungeon, averted with the Puppy Cave, and enforced with the Small Cave. The last one scales with your level; a level 1 character will find somewhat strong enemies, while a level 10 character will be overwhelmed with monsters he can barely scratch.
NPC Roadblock: Used by shopkeepers and one or two important NPCs. This can be turned to your advantage when you're low on health — run into a shop, pick up something then walk around until you heal.
Official Fan-Submitted Content: You can submit RFEs (request for enhancement) at the website. Tons of fan suggestions have made it to the game this way.
One-Hit Kill: A few monk and assassin class powers grant a very low chance to do this.
Another important example is Death magic. The good news is, players can actually obtain the Death Ray spell and use it on enemies. The bad news is, death rays usually miss except against the weakest of foes. The very bad news? Enemy spellcasters can do it too. You better hold on to that amulet of death ray resistance.
One Hit Poly Kill: The final class skill for Archers is the ability to hit several enemies with a single projectile.
And then there's the IBM guild manuals, which take this to the logical extreme: reading one makes you permanently confused. The only thing you can do at this point is pray.
Power-Up Letdown: Beastfighters can summon bears and/or silver wolves at level 25. Sounds cool, but most of the monsters you meet will be stronger than your companions by then.
Mindcrafters gain the ability to sense the number of enemies on a level. They later get 'Eyes of the Mind' which finally shows where they are, but only the monsters with a mind. Undead and golems (two of the nastiest classes of enemy) don't show up at all.
Most classes have one or two class powers at higher levels that are quite useless. The strongest classes tend to be those that don't.
You can get a random artifact if you pray to your god at a sufficiently high piety. You might get one of the good ones, or you might get something terrible like the Black Tome of Alsophocus or Celestrix.
Press Start To Game Over: New characters generated on a (real-life) Monday will enter the game a few hitpoints short of their total. ("You feel slightly exhausted today.") Poor character design and bad luck can result in a very low hitpoint total. Put them together, and you might just be done before you started.
Probability Pileup: One of the game mechanics is that items you've identified become slightly easier to find more of. Slightly.
What are the odds that a jackal kills you? Depends how many you've killed, since killing monsters makes other, future iterations of that monster slightly stronger.
Also, some of the more powerful NPCs have confusion mindcraft of their own, which they will try to use on you.
Purely Aesthetic Gender: Though there is one difference — NPC's interactions with female PCs are affected by their appearance, but if they interact with males, charisma is used instead. Yup, shopkeepers are sexist.
Averted by the frogs that randomly show up in pools, and by Skriek the Ratling, who gives women a 50% discount on his keys.
Also, females receive +1 to dexterity at game start as opposed to the male's +1 to strength. That difference is easily covered by natural variance in stats, however.
Random Drop: Go see this game's entry there. That's all I'm saying. On the bright side, you can also find artifacts this way, though it is rare.
Not only are some items cursed, a few particularly nasty items are auto-cursing. They will scan as benign, but turn cursed as soon as you put them on. Only Greater Identify or the equivalent scroll reveals this.
Dungeons vary in difficulty, and lethal high-level ones rarely come with a warning label (other than Beef Gate). Naive (or reckless) players may walk right in.
Some artifacts give you nice bonuses, tempting you to equip them, but they also quietly add to your corruption counter, slowly turning you into a mutant freak.
Some gravestones read "Great treasures lie buried here." Dig one up at your own risk.
It doesn't say that the treasure won't be guarded.
Screw the Rules, I Have Money!: There is a trainer who can train your stats beyond the normal 20-25 points, but he requires obscene amounts of gold pieces. Combined with the casino which allows for you to easily make obscene amounts of gold pieces, you can easily raise your stats to very high levels. Theoretically, if you win money at the casino you're forced to spend it — and quite a bit more besides — at the hugely overpriced casino store if you want to progress, but that can be bypassed by teleporting the guard blocking the way.
And the "Heir" talent, a hard-to-qualify-for 1st level talent that starts you off with a magic item dependent on your class. These range from specialized armor and awesome wands to the near-essential Sprint Shoes: Seven League Boots. Very very useful for getting places before Bad Things Happen.
Did you deeply offend your deity by committing sacrilege against the very principles of your faith? Sacrifice a couple hundred grand and you're his bestest friend again.
Subverted with champion crowning, however. You only get that once per game, no matter how many gods you impress.
Self-Imposed Challenge: Nearly every aspect of the game has been played to death, so there are quite a few of these. One of the most extreme was playing (and winning) with a weight limit of 100s. A normal player would finish the game holding 30-50 times that much in inventory, never mind their equipment. In addition, several artifacts that are needed to complete the game each weigh 100s, so the PC had to be naked and carrying nothing else (including food, armor or weapons) while moving them to the bottom of the dungeon.
One player nearly won the entire game with a completely blind character. The only reason it wasn't finished was because there is a particular endgame action that cannot be done while blind.
Shoplift and Die: Stealing from a shop angers the shopkeeper into summoning thugs... and going after you himself. Thrown gold pieces hurt.
More like, "Gold pieces are lethal." You will only ever underestimate the Casino Shopkeeperonce.
Shout-Out: Many. Notably, you can find phase daggers, moss of marelion and morgia root, which originally appeared in Beyond Zork, Infocom's oddball text adventure/RPG hybrid.)
"They say that at times, things can get zorky."
It is also possible to find Sting, though it doesn't shine blue if goblins are near.
Hurthlings always start the game wearing a cursed ring.
There are many, many, references to Lord of the Rings. Non-hostile orcs will ask you about the one ring, and black hurthlings (hobbits) will ask about their precious, and can be tamed with fish, as some other examples.
Slippy-Slidey Ice World: Spiked boots don't work. It's also not friendly to reptiles. Thankfully, it's possible to dig your way through part of it.
Spell Book: These can be found randomly in the dungeons, and teach a limited amount of castings upon reading. Once they have been read enough times, they disappear into thin air.
Square Race, Round Class: All classes are open to characters of all races, which means there are exactly 200 possible combinations. Troll thieves are just the beginning...
In fact, some of the stranger combinations (notably Trollhealers) are so powerful that they are canonical pairings. Even combinations whose stats are directly at odds (Troll wizards or Hurthling barbarians) can be strategically sound choices, since versatility is hard to acquire while the lack of power will eventually be compensated by experience.
Tactical Door Use: Closing doors will stop many enemies, allowing for a breather or an easy escape. Exceptions include anything smart enough to operate a door (locking it works though) and creatures that can pass through walls, most commonly ghosts. Particularly strong creatures can smash them outright though.
Take Your Time: Inverted by The Corruption, which will corrupt your soul faster after 90 in-game days have passed. Played straight by Khelavaster, whom you find surrounded by chaos spawn, within an inch of death... and yet if you turn back and take a few months to find an amulet of life saving, he's still standing on that same staircase, waiting for you to talk to him so he can die already. Protip: don't talk to him before giving him the amulet.
One way of completing both the puppy and the bandit sidequest relies on triggering this: dive down to the bottom of the Puppy Cave, dodging monsters as you go. Pop down and straight back up the bottommost staircase. This counts as getting there in time & generates a living cute dog that won't die as you're trudging around the forest in the overworld. Now all you have to do is get back out without reaching lvl. 6...
Teleport Spam: Blink dogs teleport and will summon more of their kind for help. This results in a large group of blink dogs that all teleport around the level all the time.
Training from Hell: Strength can be trained by walking around everywhere while heavily burdened. It's nearly required for beefing up weak starting characters. Repeatedly using certain skills also trains them.
Try Everything: As in, "try using everything in your backpack to save yourself from a messy death".
Unidentified Items: The game has Scrolls of Identify and an Identify spell. However, whether these tools are cursed or blessed makes a world of difference. A normal scroll of identify will only identify one type of items at a time. A blessed scroll of identify will identify your entire inventory and show what items are blessed or cursed. A cursed scroll identifies a single item. There's also the Scroll of Amnesia, which will remove knowledge of most inventory items instead.
Unwinnable by Insanity: The Pyramid and Minotaur Maze both close up once you reach a certain level (17 for the Pyramid, 31 for the maze). Anything inside is Lost Forever once they close. If you drop one of the Chaos Orbs, leave, and then gain that level, the orb will be irretrievable. However, this is nigh-impossible to do unintentionally.
The Wish spell is a nice example of this. By the time your character has the capacity to cast it, you almost certainly have everything you need to finish the game anyway, and there are few things that you can wish for that are worth the loss of 10 stat points the spell also inflicts on you.
Vancian Magic: When you learn spells, you get a limited number of castings for said spell. On the other hand, your character usually learns a hundred castings or so per spell reading. Unintelligent characters learn fewer or not at all.
Also, casters have Power Points, which ALSO limit how often they can cast spells. When you run out of power points, you either stop using magic or start casting from hit points.
Healing injured monsters is a fast (if risky) way of gaining Lawful alignment.
Videogame Cruelty Potential: Blup the baby water dragon in the first village is looking for his mother. If you find and kill her, then tell him that you've found her, he thanks you then flies off to meet her. Also in the starting village, you can get a quest to rescue a young girl's puppy from a spooky cave. It is possible to bring said puppy back to her, and then kill it and eat it while she watches. There's also a chance the puppy will become hostile, and maul her to death.
A more complex example: there is a special reward a player can get for avoiding killing any cats, even hostile ones. However, there isn't a rule against using a Baleful Polymorph to make it not a cat, leading it repeatedly over an acid trap, wearing a ring of fire resistance and placing yourself in between a cat and a fire-breathing lizard, or exposing it to The Corruption until it becomes a twisted alien being. 'Course you may want to avoid that last one.
Monsters killed by companions, familiars or undead minions are not on your conscience, as far as the game is concerned, which provides another simple workaround (simple at least for anyone with pets, available to any class but easiest for bards and necromancers).
If you have a wand of trap creation, you can aim it right at the cat and, if you get lucky, kill it instantly without penalty.
In another example, you can kill a beggar, poison the corpse then feed it to another beggar (which quickly kills the second beggar).
Bottom line in this game: you're free to attack anyone or anything if you so choose. This includes children, cowering near-dead foes, non-hostile passersby, etc.
Villain Protagonist: Your character is fully capable of worshipping Chaotic gods and performing quests in evil ways... and there is a specific ultra ending just for evil characters. You go to the Chaos Plane and fight the Ultimate Chaos God just like in the goody-good ultra endings... and then kick his ass and take his place.
Wallet of Holding: At some point you'll most likely find yourself lugging around tens of thousands of gold coins. They're light but not completely weightless, though.
Weaksauce Weakness: Gremlins are vulnerable to light; the Light spell is one of the easiest spells to learn. It doesn't do that much damage, but it's oh-so-satisfying to kill these otherwise annoying breeders by repeatedly turning the lights on.
Andor Drakon, the ElDeR cHaOs GoD, is vulnerable to stunning, confusion, paralysis, and thrown potions of cure corruption. The last one is particularly effective, as it causes him to lose several of his attacks.
When Trees Attack: The Animated Forest is a level packed with animated trees, most of which won't bother you. However, some of them are hostile, and there's so many trees that all you can do is slowly push through the crowd. Trying to use fire is...inadvisable, to say the least.
"You are starving! You are starving! You are starving! You die..."
YASD: You will suffer this in ADOM if you just Attack Attack Attack, but even veterans aren't immune to forgetting to equip a weapon after dropping it on an altar. Other YASDs: accidentally using Fireball on your vastly more powerful companion; fighting ghuls without paralyzation resistance; coming across a greater mimic and trying to melee it; stepping onto a chaotic altar when an intelligent chaotic monster is nearby, kicking stairs to train your strength (no, seriously) and many, many more.)