Roguelike column thumbnail ['@ Play' is a bi-weekly column by John Harris which discusses the history, present and future of the Roguelike dungeon exploring genre.]

Nethack (and Hack) keeps coming up again and again in this column because, after the original, it is the most Rogue-like of them all. Rogue is a game with profound design: changing even the tiniest bit affects everything else.

Of all the roguelikes, the Hack games are those which most recognize that Rogue is an interesting game for reasons other than its turn-based tactical combat. Many of these games pay lip service to some of Rogue's more profound features, especially item identification, without really embracing them. In Angband, attempting to ID some things by experimentation is a really bad idea, because of the existence of items that can instantly kill a player who uses them, and anyway players can usually find all the identify scrolls they need through the town shops. Dungeon Crawl's maintainers admit that it downplays its item identification game. And all of these roguelikes weight item generation by level, which upsets the identification game by making it even more unlikely that very useful items will appear early on.

Nethack's deeper features tend to be extensions and elaborations of Rogue's: its identification game, its objects with heavily programmed functions, and the secret uses of many items. And these are the things that roguelike fans who don't like Nethack disapprove of. I maintain this is because they've been trained to enjoy "mainstream" gaming first, which tends to be devoid of real strategy, values providing the player with an "experience" more than being a game that can be lost, and are forgiving to the point where he can't really ever die: he can always return to a previous save, after all. The absence of those things allow precisely the aspects of Rogue that make it worth playing at all.

My own thinking regarding Nethack's design has undergone some adjustment over time. Most people who become fans of the game upon first exposure like it for being Rogue Deluxe. After further play, they notice that although there are many more secret features in the game, after learning them all they make the game easier than the original. Some of them appear unbalancing at first, but actually they seem to be rather deviously balanced. After many games, it sometimes turns out that they may not be balanced as well as it seemed at first, and some of it actually overturns some of Rogue's elegance out of the exuberance of adding new stuff.

Yet that exuberance is an important part of Nethack. It is filled with interesting things, and as any worthwhile game designer will tell you, it is profoundly difficult to put something really interesting into a game. There are not actually that many things that can be put into games, and the artificial strictures placed upon them by "modern" game design, like returning to old saves, overbearing balance, hard-coded levels, and even the tutorial aspect of the early sections serve to restrict the designer's imagination even more. Nethack's Dev Team seems to be saying through Nethack that it's more important to add new cool stuff than to make sure it's properly balanced, and provided that it really is cool, I tend to agree with them.

But this is not to say that balance isn't important, nor that the Dev Team isn't concerned with it. What they're really about, in my opinion of course, is adding cool new features yet making sure they "fit" with the rest of the game. Sometimes they get it right immediately, sometimes it takes them some time to figure out the problem and fix it, and sometimes the problem survives. Sometimes it survives long enough that it becomes part of the game, and the thought of removing it becomes unthinkable. Sometimes it even turns out that the misfeature isn't so bad after all, or later features remedy its balance issues, but also sometimes they aren't so fortunate.

Here is a short list of some of the more immediately evident of these features, and their current status:

djinn28.pngProblems that have been fixed:

Wishing for wishes
Wishing items used to allow the player to wish for objects that could then be used to get wishes. In the case of wands of wishing (which used to be fairly common in hell), the net gain in wishes would be positive.

This was fixed long ago, although it can be noted that drinking smoky potions, no matter what they might be, may very rarely summon a djinn who could offer a wish. There is no restriction of the wishing of smokey potions, although the wish chance is slim enough that it's hardly an exploit.

nurse28.pngNurse dancing
Players wearing no clothes and wielding no weapons get healed, not harmed, from the attacks of nurses. If the player's fully healed, then a few of these hits will raise his maximum hit points.

This is a prime example of a feature that other games would either never have included, or if they did would remove rather than work through balancing it into the game. In Nethack, taking off all your clothes can open you up to quick death from suddenly-appearing monsters, especially liches, but there are other checks as well. There's a limit to how HP can be raised this way, and when a nurse heals there's a chance it'll vanish from the game, not just teleport as with nymphs, leprechauns, etc.

polypile28.pngProblems that were balanced around

Polypiling
Zapping a wand of polymorph can turn a monster into another kind of monster, but if the invisible ray travels over items it'll turn them into other, random items of the same type, i.e., weapons become other weapons, armor becomes other armor, gauntlets other gauntlets, rings other rings, potions other potions, and so on. Equipment keeps its enchantment, wands retain prior number of charges, and so on.

The major incentive to explore dungeon levels, as opposed to just heading for the stairs, is to find new random treasure, but if you can get that with a quick zap from a wand? And if it'll affect all items over five spaces, even if there's hundreds on that spot? This got fixed by causing large stacks of polymorphed items to "merge" into smaller piles when changed, discarding large amounts of stuff, and the creation of golems, which are sometimes strong opponents and who also take some of the objects out of the pile.

succ28.pngSuccubus dancing
Succubi and Incubi are a particular type of demon that can be... "consorted with"... to make special things happen. With high stats and luck, the chances of the things being good ones can be very high, even guaranteed, and one of those things is gaining an experience level.

The balancing from this is two-fold. The direct method, and the indirect. As for direct, such an encounter leaves the player mostly unclothed, like with nurses, the monster always ends up with "a headache" afterwards, unwilling to do it again for a random number of turns, and after a while getting a severe headache that disables its benefit-generating ability with permanence. To get benefits consistently from a foocubus also requires the player have high scores in Intelligence and Charisma, the two most difficult stats to raise (they don't change through exercise), and the benefit granted is chosen from a list out of which level gain is only one element.

The indirect balance is much more profound, and is actually a balance against all the instant level gains the game offers. In many other games arbitrary sources of level gain are obviously a balance flaw, but Nethack's monster generation system means it's not as bad as it might be. The traditional way to select random monsters is to pick from a list that's hard-coded for each level. Nethack does it by selecting monsters, from a big list of all those that can appear in the current dungeon branch, by taking the average of the player's level and the dungeon level, and trying to generate monsters of around that difficulty. This means that gaining levels itself will increase the difficulty of monsters generated, by about half the rate the player advances.

pudding28.pngCurrent problems

Pudding farming
When monsters greater than a certain difficulty are killed, in addition to sometimes leaving a corpse and always dropping what they were carrying, sometimes they'll additionally leave behind a random item. This may not make sense but it does fulfill a game role, since monster possessions are not very random but vary according to the monster type. For example, soldiers get military equipment, and elves and dwarves sometimes get cloaks, mithril and appropriate weapons. The random item drop thing provides extra loot incentive for killing strong monsters even if they don't ordinarily get treasure.

One of the monsters that can drop random stuff is the black pudding. Every time a black pudding dies, it can drop treasure. But whenever a pudding is struck by a weapon that does more than one hit point of damage, it may divide into two puddings. Each of these monsters now has a chance of dropping random loot, and they may also further divide themselves. Split puddings end up with half the hit points of the original, but they can heal back up to maximum.

Some players have pushed this into an epic exploit. By engraving a certain word on the ground, one that causes monsters to avoid spots on the floor, around their location except for one space, then purposely filling the level with puddings through division, they set up what is known as a pudding farm. They endlessly kill puddings, leaving behind vast quantities of loot over time. The chance of getting something from a kill isn't large, and the chance of getting something really good like a wand of wishing is extremely small, but after killing tens of thousands, or more, puddings, the small chances add up.

The only checks on this tactic in the game are the usual ones against sitting in one place doing very little, mostly hunger (pudding corpses, while acidic, are edible), and the tremendous ennui that results from playing the game this way. Players strong enough to divide puddings this much and survive are probably strong enough to win the game already, or could become so with little trouble, but some kinds of conducts become much easier through farming. And by producing huge amounts of loot, gaining high scores becomes much simpler, increasing Nethack's already-great score inflation.

pest28.pngPestilence farming
I've mentioned this before (in Giant Eel Stories), but as an advanced case of farming, which has taken scores up to MAXINT-1, it's interesting.

Using a somewhat similar setup as with puddings, players can repeatedly kill Pestilence, one of the three Riders at the end of the game, for large score awards. By restricting how other monsters can approach the player, and when playing a telnet game (such as through alt.org), the process can then be automated through a macro, attaining absurdly high scores.