Here is a walkthrough of all the campaign levels completed on veteran difficulty:
Southport:The Outskirts:Pagras:Twin Rivers:Silveroak Forest:The Citadel:Goldstep Mines:Icewind Pass:Stormcloud Temple:The Wastes:Forsaken Valley:The Dark Tower:Ruins Of Acaroth:Hushwood:Bandit's Lair:Sarelgaz's Lair:Glacial Heights:Ha'Kraj Plateau:Rotwick:Ancien Necropolis:Nightfang Swale:Castle Blackburn:Rotten Forest:Fungal Forest:Pit Of Fire:Pandaemonium: