very easy way to beat the shadow: Put a charged bolt shrine where it enters(middle of the top) and put in a lvl 8 gem when the shadow appears. The shrine kills the shadow easily. + to keep it up
Against Colossus: all 3 magical class (golem is weak against magic) and vamp, hobbit, and zerglings... err i mean goblins... This little bastards keep him far from your hero. The Collosuss said 1 monitor far from my hero: "I killed so much goblin today so i rather die than kill anymore.." All six platina sword + if it helps