Nightmare difficulty was introduced in patch 7.13. While not yet generally available, players who have bought the Quest for the Lost Eternia Shards Complete DLC on Steam can host maps with Nightmare difficulty. Any player may join these, regardless whether or not they bought the content.
Differences From Insane
The increase in difficulty from Insane to Nightmare is much greater than the increase from Hard to Insane. There are also four major differences from normal game play:
- While player and tower health are scaled up, player damage is scaled down to roughly 1/6 of normal damage and resistances are reduced by 33%. Tower damage however, is scaled up. Tower area of affect also appears to be reduced, most notably on monk auras where a smaller diameter is clearly visible.
- Spiders will spawn in random locations (i.e. not necessarily coming from normal spawn doors, but dropping from the ceiling) on every wave on every level and will preferentially target heroes and defensive physical towers.
- Sharken and Djinn will spawn at the normal spawn locations, and wreak havoc on your defenses!
- Goblin Copters will spawn at locations where wyverns spawn, meaning they don't spawn in maps that do not support Wyverns.
- Ogres will spawn much more often, and much earlier than usual, such as Wave 1 on The Deeper Well. Heroes without significant upgrades to damage resistances on their armor equipment may find themselves killed with one hit. Ogres on nightmare also may have elemental resistances. The Ogres are very strong individually, but their real strength is in numbers. On the last wave of The Deeper Well, four ogres spawn!
- The reward for this increased difficulty is Mythical, Transcendent, Supreme, and Ultimate loot! Not only is it better than Godly quality, but the step up is considerably more powerful, with sometimes four times the base stats and three times the available upgrades on early Mythical loot, compared to late Godly counterparts.
- The casting is significantly faster.
- The effectiveness of attack pets is significantly increased.
- If you're starting Nightmare, look into Hero Shops to buy cheap Mythical items. Sometimes you can find a piece of gear for 1-2 million Mana, and it will pay for itself once you get Mythical loot dropping for you!
- Remember that you will get a set bonus for wearing all armor of the same class (Leather, Mail, Chain, Plate, Pristine). For Godly armor and below, it's an extra 25% stats on every stat that's on your armor. For Mythical, it's even better, with a bonus of 30%! However, for the Mythical bonus, all other items must also be of Mythical (or higher) quality.
- Ogre troubles? Focus on single-target towers and walls. A squire with a high block value can tank the ogre while your towers kill it very easily. Note that elemental towers may be ineffective against an ogre if it's of the same type, so don't overload on elemental damage.
- Dying too much? Before you spend 50 points upgrading hero health, upgrade resistance instead. Having 45% physical resistance will allow you to last almost twice as long in nightmare, which is more effective than spending those points in Hero Health.
- Cover your towers. A brilliant defense means nothing if it's webbed. Your defense should be as close to the crystal as possible, to minimize the chance of spiders spawning behind it. However, always have towers pointed inwards to deal with spiders, as they seem to love spawning on your crystal(s).
- Wyverns fly a lot faster than normal. Make sure your towers have sufficient range and attack rate. You could sometimes need some extra defenses to handle Wyverns (additional offensive tower, Ensnare Aura, or even Darkness Trap along with Ensnare Aura).
- Distract Ogres. Having three Ogres biting at your defenses is better than four. Simply move behind them within melee range (even if you're ranged) and attack them. This should get their attention and they'll turn around. You'll have enough time to get out of melee range of the ogre, but don't go too far or they'll lose interest and head to the crystal as normal. If you lose the attention of an Ogre for any reason, get within melee range again and attack. This should get him to focus on you again.
- The Apprentice Guardian and Huntress Guardian familiars will be very useful and assist your towers greatly. The towers that it buffs can easily do more then twice their damage. Even the Hard summit reward pets are worth their weight in gold, and will contribute more to overall DPS than any DPS pet.
- Endless Spires is a good map to start Nightmare as there is lots of room to kite the ogre in the first wave.