In roguelikes, scumming is a strategy that consists of collecting easy rewards with low risk, e.g. when a high-level character visits levels suitable for low-level characters, since they pose no risk but do offer some marginal rewards.
XP Scumming (Grinding)
Monster grinding was prevalent before version 0.6.0. Players (especially the foodless Mummy) would spend thousands of turns waiting on early levels for monsters to respawn, kill them without any risk, and gain XP. This rewarded tedious play behavior, and trivialized later branches since players entered them with a higher level (and power) than intended. This was deterred by bringing in out of depth monsters, before monster spawning was removed all together.
Players can still scum in Crawl due to the infinite nature of the Abyss and Pandemonium, though they have to fear dangerous and hard to cure mutations. Also, characters who are able to stay in there for extended periods of time are likely able to just win the game.
Start scumming is a form of metagaming; restarting your game until you get a good start. This can be done for items, but some species and backgrounds have a degree of randomness to them:
- Wanderers and Delvers may want to restart in order to better opening (better items for Wn, the Temple for De).
- Demonspawn and Djinni may want to restart for a better mutation or spell set, but both take time to settle in.
- Draconians may want to get an optimal colour, though it often doesn't have a big impact on the game.
Keep in mind that, unlike similar games in the genre, this does count towards your online winrate.
The spell Alter Self (long removed) allowed you to reroll mutations endlessly, provided you had food to do so. Most other sources of random mutation are finite (if monsters and items are finite), except for Xom. Xom will naturally get bored, but is easily entertained by the Confuse spell (or spell miscasts).
While technically possible to reroll Malmutates until you get a positive set, the bad mutation weighing makes it an infinitesimally small chance to get any sort of good mutation set, being much more likely to Mutation Resistance 3 with a set of terrible muts.
Luring is a perfectly fine strategy of its own. However, shouting near the stairs for thousands or even millions of turns for wandering monsters to come is generally taking it too far.
More of a form of cheating, save scumming (as called in games with persistent saves) is where you continously load a save to try over and over again. This should be impossible in online servers, but your save file can be copied in an offline build. An easier way to save scum would be to activate explore mode in an offline game.
As a soft limit for any time and turn consuming behavior, the Zot clock (formerly the food clock) serves as a timer to start progressing the game again. However, the Abyss has no Zot clock, and infinite floors in Pan give infinite chances to advance the clock. The Zot clock can be stopped by finishing a Ziggurat, but players who do this are even more obviously able to finish the game.
Finally, the game has a hard limit of about 200 million turns. If you reach this limit, your game ends with the message:
Outside, the world ends.
Sorry, but your quest for the Orb is now rather pointless.
- The Abyss, an infintely grindable realm, stopped giving experience, piety or items, in 0.28. It gives XP/piety again in 0.29, but was made much more difficult during extended trips (similar/harder to the Pandemonium).
- Between the removal of the food clock and addition of the Zot clock in 0.26-trunk, players could abuse Xom to gain lots of beneficial mutations.
- Monsters stopped spawning post level generation as of 0.21 (barring the infinite Abyss, Pan, and while holding the Orb of Zot).
- Alter Self was removed in 0.9.
- As stated in the article, 0.6 made out-of-depth spawns a constant force to keep you moving. After more than 3,000 turns on a given level, the number of monsters that would spawn gradually decrease, until monsters stop spawning altogether after 15,000 turns. Additionally, these monsters would be extremely out of depth.
- Prior to 0.6, stats used to be randomized: there were eight stat points that would be allocated randomly, potentially encouraging restarts.