Dungeon Features

Crossing Rivers

• Swim (if you have the Swimming skill or it's less than 3 spaces wide, you'll make it)
• Swim half way across, pray for health, keep going
• Teleportation spell
• Use a wand of trap creation to set up a teleport across
• Use Frost Bolt or a wand of cold to make an ice bridge (beware weight limits)
• Use the Bridge Building skill
• Wand/spell of earthquake - ceiling rubble can create land bridges
• Get an Ice Vortex or Ogre Magus to help you build an ice bridge

Unsorted

• 1/3 chance to create herbs when you pour holy water on to the ground. (Herbs will only continue to survive on a level which had them to begin with.)

Unique levels (Pyramid, Cities, Dwarven Graveyard, etc.) obviously don't generate these random features.
Forge: 1/8 chance to be generated if danger level > 5 and level is normal level
Altar: 1/9 chance (not in DD7, ToEF4, Mana Temple, D49, and others)
Herbs: 1/6 chance, only if No Altar or Forge, DangerLevel > 2 and normal level
Pools: 1/6 chance, only if No Altar, Herbs, or Forge and level is normal level
Tension Room: 1/5 chance
Shops: Merchants 1/4 chance, regular 1/6 chance, level must be normal level (can't have exsisting shop like HMV/Dwarftown)
 Shoptypes: Wands x2, Scrolls x5, Potions x4, General Store x3, Books x2, Rings x3, Pets x1 (chances out of 20)
Trap-filled Room: 1/50 chance plus 1/10 chance if doomed -- 'shudder' message is generated randomly based on your perception, so you don't always get the message.
Royal Treasury: 1/3 chance and level is normal -- definately other factors missed here
Threaten Room: 1/8 chance and danger level > 7 -- again, message based on perception.
Rivers: 1/15 chance, available in _most_ places
Hives (Bees and Ants) are based on something kind of strange; locations probably defined at character creation.
Vaults must be in a different section, no info on them yet.

Surges of Power come simply when an artifact is randomly generated on the ground (based on creation probabilities)
estimated chances for one (or more) surges of power in a complete game: 31%

for shops...
5/6 of the Food in Terinyo is automatically Large Rations
Wands of Wishing are 8 times less likely to spawn in shops (7/8 chance of deleting them if created)
Scrolls of Chaos Resistance = 12 times less likely
Ring of Djinn summoning = 5 times less
Cure Corruption = 6 times less
Gain attributes = 40 times less
Potion of Water = 2 times less
Potion of Stat = 30 times less
Potion of Potential Stat = 20 times less

If you don't have the herbalism skill at all, then an herb bush will
always decrease in status when picked (so you can pick 3 herbs if the
bush is full of blossoms).

Otherwise, you have a HerbalismSkill / Rand(160) chance for the bush to
not lower in status; so 3/8s of the time the bush will still go down a
rank at 100 herbalism. Some fairly brief tests gave an average of about
8 herbs picked

if HerbalismSkill > Rand(110) = Uncursed

THEN (only if it passed the first check)
if HerbalismSkill >= Rand(140) = Blessed

Level 18+ farmers now have a 1/2 chance of anything cursed turning
uncursed at this point, immediatelly followed by a 1/2 chance for
uncursed to become blessed. (so lvl18+ farmers still have at least a 25%
chance of getting a blessed herb, even if they somehow didn't have the
herbalism skill ;)


Non-farmers get about 65% blessed herbs, 26% uncursed, and 9% cursed at
100 herbalism; level 18+ farmers should get around 80.5% blessed, 15%
uncursed, and 4.5% cursed.