Core Mechanics
Being a roguelike that has been passed around like the proverbial town bicycle, the mechanics of FrogComPosBand are an agglutination of lots of people's ideas of what might be fun over an extended period of time. Needless to say, they're complicated.
Regardless of your character choice, you'll have the same basic stat categories: strength, intelligence, wisdom, dexterity, constitution and charisma. The game again shows it's D&D influence here by adopting the 3rd edition style of stat progression. In that system, stats start at zero and go up to 18, which is considered peak human ability. Above that, stat increases are incremented by the 18/10 notation, meaning that for every 10 after the slash in the total is basically an extra point in that stat.
Attributes can be increased by equipment, temporary buffs, rare and expensive potions, by hitting level up milestones, or by defeating guardians of different dungeons throughout the world.
Backing up a bit, Nethack and older games started you out in the dungeon and had towns where you could buy and sell equipment randomly found throughout. Somewhere along the line, people added an overworld and static towns that you would teleport to back and forth from the dungeon. Like other variants, FrogComPosBand has an overworld with multiple dungeons as well as multiple towns to buy, sell and complete quests in.
One of the other core systems of the game is the resists system. As you might expect, monsters can cast spells and breathe various elements to try and kill you. This damage can be mitigated somewhat by having resistance to that element.
Resists can come intrinsically; if you're playing as a red dragon it wouldn't make sense to be vulnerable to fire. But the majority of your resists will come from equipment.
Press C (by which I mean shift+c, it has to be a capital C) to see your character page. Hit page down and page up to scroll through it quickly. Here you can see what your current resists are along with what equipment, if any, is affecting them. There is tons of information on this screen, read through it all at your convenience.
As you might expect from a family of games that have been forked and maintained for more than 30 years, there are more than your basic assortment of elements. Acid, electricity, fire and cold are your basic resistances, but by no means are they the end of the story. Poison, light and dark attacks also exist but are less common than the basics. Then you get into the more exotic, or ‘high’ resists: confusion, sound, shards, nether, nexus, chaos, disenchantment and time.
Interestingly, each element, base and high, has their own special effect if you get hit with it without any resistance. Acid degrades your armor, reducing your overall AC and making you easier to hit. Electricity can destroy jewelry in your inventory, fire can burn scrolls and books, and cold can shatter potions you are holding.
Poison starts a counter that slowly decrements, causing damage each turn until it expires or is cured. Light and dark can blind you and also change the lighting status of the dungeon.
Confusion is a status effect that causes you to move randomly and prevents you from using certain magic and items. Sound can stun you, reducing your ability to hit monsters and cast magic. Shards cause cuts, a more severe status that behaves similarly to poison. Nether is used by most undead enemies and reduces your maximum HP, stats, experience and overall level. Nexus can teleport you, polymorph you or permanently scramble your stats which can be devastating to the unprepared. Chaos has several random effects including extra damage, stat loss and healing the monster that hit you. Disenchantment permanently reduces the bonuses your equipment provides you. Time is the rarest element found in the game, only used by a handful of monsters, resistance provided only by a small number of items. Getting hit by it can ‘turn the clock back’ and reduce your stats, experience, and level.
Having a resistance to an element reduces both the damage you take and the likelihood of receiving a negative effect like potions shattering by like 90%. Having double resistance to an element reduces damage further and lowers the chance of negative effects by like 99%. When you get breathed on by a Great Wyrm of Perplexity, you're going to want all the confusion resistance you can get.
Along with all those bad things, there are several other status effects that can cause you trouble. You can be afraid, hallucinating, paralyzed, have your life drained, be slowed down, be hit by invisible enemies, afflicted by hunger, have your equipment cursed, contract an illness, get ancient blood curses cast on you, or even be crushed by earthquakes. All of these have various ways of being mitigated but the unwary can have their run cut short by any one of them.
Aside from stats and resists, there is another very important consideration for the aspiring adventurer: speed. Most roguelikes run on the basis of turns, i.e. you act and the monsters simultaneously get to act. But if you have a greater speed than the monsters you will get to act more frequently and vice versa. Underneath this system in FrogComPosBand is the energy system. In general, you get a certain somewhat randomized amount of energy each turn and the higher your speed the more energy you get. If you have above a certain threshold, you get to act. Slowed enemies take longer to cross that threshold and therefore get fewer turns. So the more speed you have, the better.
Outside of player characteristics, you've also got a rather large world to explore. Dungeons exist outside the towns with randomly generated layouts, each one with its own general theme. Some feature narrow twisty passages between rooms, some have rooms with open areas between. Some have forests that block line of sight between you and the monsters. Some have constant elemental effects that can damage you. Certain dungeons have families of monsters found within, like dragons found high in the mountains or knights in castles.
Dungeons have a difficulty rating indicated by their depth. In old versions of Angband they used feet notation, i.e. 3750’ deep, which is still referenced in some odd places in FrogComPosBand like the scrolls of Rumor that give random, occasionally helpful advice. In modern versions they use ascending level depth, meaning the higher the dungeon level, the harder the difficulty.
The overall goal of the game is to descend to the 99th level of the dungeon Angband, kill Oberon the guardian to be able to go to level 100 and then kill the Serpent of Chaos therein. Making this extra difficult is the quirk of the Angband dungeon to feature out of depth monsters. As you descend levels, monsters are generated to populate the dungeon. But in Angband, the game pulls harder monsters from its repertoire than any other dungeon in the game.
The other quirk in Angband is that certain levels are guarded by what's called a unique enemy. Unique enemies have their own specific name, generally have higher HP and do more damage than their normal versions and have special powers not present in their more common versions. Early on, you might encounter an orc boss that is resistant to confusion and can summon other orcs to his aide. Later on, uniques can get mountains of HP, breathe exotic elements on you, teleport away when their HP gets low or cast devastating spells on a regular basis. The fun really comes when the game has selected an especially nasty guardian for that level and until you kill them the stairs to the next level won't appear.
The flip side is that uniques drop better items than any other enemy type in the game. Items in FrogComPosBand come in a ridiculous variety. There are daggers, short swords, long swords, two-handed swords, rune swords, diamond edges, and blades of chaos. There are bo staffs, glaives, hatchets, scimitars, latajangs, sticks and fishing poles. There are slings, bows, crossbows and guns. There are dozens of different types of body armor, boots, gloves, shields and helmets. There are light sources like lanterns, jewelry, and crowns. There are also consumable items like potions and scrolls. There are books to cast magic from. There are magic wands, rods and staves that produce spell effects.
Equippable items come in four varieties. Normal, magic, highly magic (or ‘ego’ items), and artifacts. Magic items generally have a bonus to hit and damage or armor. Ego items come with a bouquet of enhancements like resists or extra effects on hit. Artifact items have all of the previous effects and usually one or two other things you can't really get anywhere else. By the end of the game, you will be wearing primarily artifacts. You want artifacts, you need artifacts.
Enemies can drop any kind of item at any level. There are low level unique bosses that can drop low level unique items. The deeper you go into the dungeon the better the quality of the items that drop from monsters and that can be simply found on the ground.
One important exception to this are vaults. Vaults are special areas that can be generated in any dungeon that contain treasures and monsters better and harder than you would normally find at that level. This ups the risk/reward calculation you're constantly doing while playing the game. And greed has been many a character’s fatal downfall.