It's been brought to my attention that we don't have a guide for Down Below yet! So here is a very rough one that is definitely missing things. Please add, edit, and organise as needed.

First up: you unlock the relevant quest through a Distraction from The Watcher with the subject line “I need a favour.” You may first need to check out the “Intriguing-looking hole in the ground” in any Outpost, may first need to reach level 10, and may first need to complete some early quests.

Now for miscellaneous facts and advice, which will make more sense if you've unlocked the area in-game:

• Aesthetic note: if the Map's too busy for you, check out the Map Display Settings and try disabling some stuff. You may want to re-enable some things once you've figured out what you're doing a bit better.

• You can't use grenades in fights. You can use Bangs and Whoomphs on the underground map: both kill enemies, and Bangs also destroy immediately nearby walls, which can be very useful. You have three turns to get at least two squares away from Bangs, and two turns to get away from Whoomphs, and if you're still too close you will also get hurt. Whoomphs can also be useful for creating an obstacle fire, blocking enemies from crossing it or following you down a path.

• If you leave Down Below and immediately return, the map stays the same, blasted walls and all. Every level of the map DOES have a chance to get randomly re-generated on each New Day, but you may find a level stays the same over several real-life days.

• Levels you will find Outposts on are 1, 2, 3, 5, 8, 13, 21, and 34. Level 1 will always lead to NewHome; the rest are random.¹⁾

• The deeper you go, the tougher FoeBots are. Also - and this is based on half-remembered discussions with people who knew more than I did, so if anyone can confirm or correct I'd appreciate it - the higher your HP is, the harder they hit. If you want to do Down Below a lot, be careful how much you raise your HP, because it is possibly not all upsides. (A more general gameplay tip: if you do want to raise your HP, you're generally better off using the Gauntlet in Improbable Central than spending DK points. The Gauntlet trades Charm, if you have it, for permanent HP - show up with 250 req or they'll turn you away. There's no similar way to build Attack or Defence outside of DKing, and DKing takes increasingly more work as you progress.)

• If you get knocked out, you can always post in Banter to see if someone wants to rescue you - just tell them what level you're on! Rescues are tallied up in the Hall of Fame, so players who go Down Below tend not to need any other incentive. Both of you will also be healed for free when you leave.

• If you don't get rescued, you need to either pop a Chronosphere or wait for a New Day. If you're on an Outpost level, you'll get spat out there. If you're not, it'll pop you one floor up instead, and you'll need to wait or use a Chronosphere again, & rinse and repeat until you reach an Outpost level and get ejected there.

• Apologies to hermits, but if you intend to hang out Down Below for more than short periods, a full Clan Buff is really useful - it gives you automatic healing, along with other things. Starting a Clan of your own is an option, but a serious undertaking that costs a serious amount of cigs.²⁾ Joining an established Clan for the buff is pretty normal, though some have social or story requirements, or want players to donate cigarettes towards the buff or Membership Cap. Feel free to ask about open Clans in Banter, or check the list of established Clans to try to find an active one.

• Standard advice applies: watch your Stamina so you're not fighting or travelling while exhausted. Using Monster Repellent Spray on yourself before you go makes FoeBots hit less hard, as does using a scary weapon like a Dentist's Drill - though you don't unlock that until a certain number of DKs. Carrying Medkits or Smile Drops (which are more useful for those with higher HP) lets you heal once you're down there. Targeted fighting is your friend. Jokers, mind your day's stats!

• Actually, bear in mind you can use healing items in your Inventory without getting dragged out of that screen to be attacked, so you can use several Small Medkits to heal up as easily as a Large one, or small vials of Smile Drops if the big ones are too expensive.

• Witchbloom Seedpods, the successor to the older One-Shot Teleporters, DO NOT work outside of combat while you're Down Below. At the time of writing they DO work in combat, when kept in the bandolier, but I suspect that's an oversight and might get patched eventually.
• Note: when you leave the Down Below this way, you will keep all of your scrap.

• About scrap and favour: as you kill FoeBots, they will drop scrap. This will be Unidentifiable, Useless, Potentially Useful, or Rare. (Most will show in your inventory as Unidentified; you get better at identifying them yourself with more Underground Travel xp.) When you leave the Down Below through a level exit, there will be a guard who checks all your scrap. All scrap that is not Useless will earn you some amount of Requisition and Favour with the Watcher.

• This scrap has weight, though usually it's only noticeable if you're carrying a lot. If you leave the Down Below via Witchbloom Seedpod, you may still have all your scrap as you bypassed the guard. To get rid of it, you can simply go into the Down Below and immediately leave. If however you are knocked out in the Down Below, you appear to lose all your scrap.

• It is possible to play Down Below as a careful and complex game of chess (thank you Tased for info on this approach), using Bang and Whoomph grenades and Smile Drops in anticipation of Foebots' movements, and never actually engaging in combat with them, even on the very deepest levels. It is also possible to just merrily punch your way through a level if you've got the stats for it. These are very different strategies with very different requirements.

If you have any questions beyond this, please go ahead and ask them in Banter - or if that doesn't net you an answer, tack them on the end here and you might get lucky. Good luck down there!

Note: recently some older references to the Down Below have been found, but please note these are likely outdated and no longer accurate. They are added here for future wiki editing purposes.

What's New that introduces Down Below

Places:Down Below, linked to by above What's New ³⁾

Note: Above Places:Down Below links to this page/URL as well.