This page reviews some common mistakes by new players and describes how to avoid them.
Do not attack peaceful monsters.
Some monsters are peaceful. If you look at them (with the [;] command, for example), the description will include the word "peaceful", for example a "peaceful dwarf lord". If you try to attack a peaceful monster in melee, you will be asked to confirm your attempt to attack: the best answer is [n] for no.
There are two reasons to avoid attacking peaceful monsters:
- The gods disapprove of killing peacefuls, and will exact an alignment penalty. There are more severe penalties for killing your own race (unless you are chaotic): a human player killing a human, an elf player killing an elf, a dwarf player killing a dwarf, or an orc player killing any o including orcs, goblins and hobgoblins. There are also more severe penalities for killing a unicorn of your own alignment. More details of the penalties for killing peaceful monsters can be found on this page of myths and facts about NetHack.
- However, there is no penalty for allowing pets to attack peaceful monsters, and you can even heal your pets as they do this; monsters may attack the pets but will not retaliate against you for your pets' actions.
- Many peaceful monsters are much stronger than you. In particular, tangling with a priest or shopkeeper is likely to lead to your death. (You can use a still use a stethoscope to check how strong a monster is.)
(If you ever play the variant called SLASH'EM, note that your gods will still blame you if you cast a spell of flame sphere or freeze sphere and the resulting sphere attacks a peaceful monster, even if you polymorph the sphere into another monster. See Eva Myers' spoiler on tame monsters in NetHack and Slash'EM.)
Only pray when you have reason. Praying can bother your god.
The NetHack Guidebook does not describe the effects of the #pray command, and some newbies feel that they "ought" to pray on a regular basis in order to keep in touch with their god. In fact, prayer in NetHack is always pestering the gods for help, never praising or thanking them. Hence your god does not mind in the least if you never pray, but does object if you pray too often. Once you get a negative response to a prayer, you will almost always be unable to pray until you have placated the angry deity with a suitable sacrifice.
However, prayer can save your life in an emergency. Just remember that your god's definition of an emergency may not be the same as yours. Wounds are not an emergency until you are either at 5 HP or less or at 1/7 max HP or less, and hunger is not an emergency until you are weak from hunger. Matthew Lahut's praying spoiler gives much more detail about prayer.
If your god is very satisfied with you, your god might give you a reward, which is another form of help. If it is not an emergency, then first sacrifice a corpse on your god's altar to determine whether it is safe to pray. "You have a hopeful feeling" means that it is not safe and you should sacrifice more corpses or wait more game turns. "You have a feeling of reconciliation" means that it is now safe to pray. If there is no bad message, than it was already safe to pray and remains so.
Eat only fresh corpses.
Most corpses are safe to eat when fresh, though some are poisonous (see the section on Food later in this guide to learn what is good and bad). Old corpses, though, will make you fatally ill (and have no nutritional value either). There are a few ways to cure this deadly food poisoning, but it's best to avoid it, by not eating anything that you did not kill yourself or see die. Never eat zombies or mummies; they are created by magically animating an old and rotting corpse, and such undead corpses are never safe to eat.
Should you eat an old corpse, it causes food poisoning, and "FoodPois" will appear on the status line. (This is a different form of poison than if you eat a poisonous corpse, such as a kobold corpse.) This is an emergency. Since almost nothing else will work, you might need to #pray, but if you have a way to cure sickness (with the spell or potion, or by [a]pplying an uncursed or blessed unicorn horn), then use it. Once you have food poisoning, immediately try to cure it, because you only have a few turns to live, and that unicorn horn might not function the first few times.
Do not eat while satiated.
If you eat while satiated, there is a risk of choking over your food and immediately dying. Eating once you have reached the point of satiety at which the game tells you "you're having a hard time getting all of it down" is particularly dangerous. Experienced players may be able to tell when they can safely eat despite being satiated, but it is safest for novices not to try it. So, if you want that resistance from a monster corpse, but you are satiated, you might choke and die if you try to eat it. The wearing of an amulet of magical breathing will eliminate the risk of choking, and a tinning kit or an ice box will keep food fresh for later.
(As long as you are not satiated when you start eating, you should always be permitted to finish your meal. However, owing to a bug this may not apply if you save the game in the middle of a meal. At least one character has died from this.)