The difficulty overhaul: hard modes are systems now

What changed on Hard, Epic and Legendary in The Ember Depths: summon hunters, boss enrage, bigger packs, stingier stairs, and the full table of numbers.

A Legendary player wrote in to say they were breezing through. Quillon took it personally. The hard modes used to be the same dungeon with bigger numbers; now each one takes away a crutch: minions that tank everything, gear far above the curve, potion chugging, long careless boss fights and over-levelled heroes strolling through gentle dungeons.

What the hard modes do now

Summon hunters: on Hard 30% of foes walk straight past your minions and pets to reach you (50% on Epic, 70% on Legendary). Summons also take more damage, and melee swings cleave into the summons in front of them.
Bosses enrage: a boss still standing after 240 s on Hard (200 s Epic, 160 s Legendary) flies into a rage and hits harder every 15 seconds. A damage check, not a wipe timer.
Bigger packs, more elite packs and more affixes per elite (up to 4 on Epic and Legendary).
No rubber-banding down: on Epic and Legendary a fragile build no longer makes foes softer, and an over-geared hero meets tougher foes than before.
Stingier stairs: less healing between floors, and on Legendary no free flask charge. Potions drop less often. You lose 25% of carried gold when you fall on Legendary.
Over-levelled heroes back in early dungeons now meet foes raised to match them, without the gentle early-act discount.

Loot scarcity

Legendaries were raining. They drizzle now: the pity timer is slower, a boss's first kill no longer guarantees one, set pieces and Mystery Cache jackpots are rarer. The hard modes still pay more (XP, gold, magic find and a faster pity), just less than the danger they add. Legendary is for players who want the fight.

Every number, every mode

Difficulty modes, straight from the game's rule table
	Easy	Medium	Hard	Epic	Legendary
Foe HP / damage	×1 / ×1	×1.5 / ×1.5	×2 / ×2	×3 / ×3	×4 / ×4
Rescaling floor (HP / dmg)	×0.85 / ×0.75	×0.9 / ×0.85	×1 / ×1	×1 / ×1	×1 / ×1
Foe HP per sellsword	none	none	+16%	+23%	+29%
Rescaling ceiling (HP / dmg)	×1.35 / ×1.35	×1.45 / ×1.45	×1.6 / ×1.55	×1.8 / ×1.7	×2.5 / ×2.3
Pack size · elite packs	×1 (max 8) · —	×1.3 (max 10) · +10%	×1.6 (max 12) · +18%	×2 (max 16) · +28%	×2.4 (max 20) · +38%
Extra pack per room	—	15% chance	25% chance	50% chance	70% chance
Ordinary kills pay (loot, gold; XP is full)	full	67%	50%	37%	28%
Elite affixes	baseline · max 3	baseline, 50% chance of +1 · max 3	+1, 30% chance of +1 · max 4	+1, 50% chance of +1 · max 4	+1, 80% chance of +1 · max 5
Elite HP / damage (extra)	×1 / ×1	×1.15 / ×1.1	×1.3 / ×1.2	×1.5 / ×1.35	×1.7 / ×1.5
Boss damage (extra)	×1	×1	×1.05	×1.1	×1.15
Boss soft enrage	never	after 240s, +10% per 15s	after 200s, +15% per 15s	after 160s, +20% per 15s	after 120s, +25% per 15s
Elite & boss special cooldowns	×1	×0.95	×0.9	×0.85	×0.8
Foe speed · aggro range	×1 · ×1	×1 · ×1.1	×1.04 · ×1.15	×1.06 · ×1.2	×1.08 · ×1.25
Summon hunters	none	30% of foes	50% of foes	70% of foes	85% of foes
Damage summons take	×1	×1.3	×1.5	×1.75	×2
Melee cleave onto summons	—	25%	40%	50%	60%
Stairs: heal · flask	35% · +1	35% · +1	25% · +1	20% · none	15% · none
Potion drops	×1	×0.9	×0.75	×0.7	×0.6
Gold lost on death	10%	15%	20%	25%	30%
XP	×1	×1.2	×1.4	×1.6	×1.8
Gold find · magic find	— · —	+20% · +25%	+35% · +50%	+50% · +80%	+65% · +110%
Legendary pity	normal	83% as long	67% as long	53% as long	42% as long
Drop item level	foe level	foe level +2	foe level +3	foe level +4	foe level +4
Elite drops	normal odds	normal odds	≥1 rare+ each	≥1 rare+ each	≥1 rare+ each
Boss items	4 + 1 epic+	5 + 1 epic+	6 + 1 epic+	7 + 1 epic+	8 + 1 epic+
Boss extra legendary	—	—	—	10% (25% unique)	20% (30% unique)

Change it at any time at Vhoruun's Effigy by Hearthold's north gate (since v0.10.0; in a dungeon, a change applies from the next floor's foes). Hardcore heroes choose between Hard, Epic and Legendary only.