Orcs Must Die!

If you are going for this, you should be fairly experienced with the game. Please note these differences when playing Nightmare mode:

* There are no "breaks" where the game waits for you to hit Select before sending the next wave.
* In fact, there is no set up time - the waves will start as soon as you leave the trap selection screen. Because of this I'd often pick no traps to remind myself of the level layout then restart the mission picking the appropriate traps.
* Guardians never get back up if killed. If you use Archers you must protect them! Paladins are still beefcakes though and rarely die with the life regen upgrade (Steel Weaver).
* Most Orcs now have shields, armored Ogres show up on the first level. Levels have a lot more enemies than they did on War Mage difficulty.

I mainly stuck with the same strategies as my War Mage/5 Skull run, using upgraded Tar Traps below Clockwork Maces supported by Paladins. I now add Wall Blades into those kill zones though for extra damage to Ogres. Some levels really call for a few of the Mushrooms to help turn some Ogres against the hordes.

If you are in a bind you can hang out by your rift as it grants bonus health and mana regen and spam spells to kill off things that get by your traps. This is especially useful early in levels before you set up your kill zones.

Once again I can provide level specific tips if you are stuck and would like to hear how I got through a level.

Would Like to add a couple of things here. Just finished this and made #1 and #2 slot on leaderboard on a few maps so I know a little about this =)

as Jorax stated its really hard to say anything about the map as each one is unique. But I can tell you my mainstay traps/spells I used and kept most of the time also some tips you may miss.

NOTE: at the start of each round in the trap section it shows what orc/troll ect are on the map at top of screen. adjust accordingly. aka you dont need an ice amulet for frost giants but its great for flyers. Anyways...

PALADINS (you will use these alot)
Lightning ring (best spell)
Ice amulet
Brimstone. (people pass this up but its one of the best traps out there especially for kobolds)
Tar traps tar traps tar traps.........


TIPS:
Special note on the spells.

#1)
I did not realise this till near end of game of my first playthrough so im sure someone else missed this. but if you use the left trigger instead of right it does a massive amount of damage but also drains alot of mana so be cautious.

#2)
I always used steel weaver never once went with any other one. Always stuck to the guardian tree.

#3
Paladins are great tanks. If you trap near them they will tank while you can cast lightning spells.

#4
Dont use archers unless there are flyers on the Board, you can keep them safe, or the board is designed for them.They are really weak and go down to fast in nightmare mode. I used ballista instead of archers in the final few boards except stairs of doom.

#5
Mushrooms. These are overlooked but will save your butt on a few levels. Play it by ear and see how it fits in your rotation.

Heres a link it will get you started.
http://www.xblafans.com/orcs-must-die-complete-guide-27403.h...
This guy has some good tips but you will most likely have to tweak them as he relies alot on magic. Just keep the pointers in mind. Good idea maybe to watch a video before you do the board so you can get an idea of everything.

Anyways hoped this helped someone.