THQ has promised to upgrade, for free, all PC, PS3 and Xbox 360 pre-orders of Darksiders 2 to Limited Editions. There's no mention of the Wii U version.
Limited Editions come with a code to download the first single-player content pack Argul's Tomb.
There's also a Collector's Edition, which offers a life-sized Death Mask and display stand, in-game Shadow of Death armour and scythe set, digital copy of the Darksiders 2 soundtrack and a hard-cover Darksiders 2 art book.
The Collector's Edition sells for around $99. European retail partners haven't been specified. You'll only be able to buy the PC Collector's Edition from the THQ.com store.