Mandalf is the wizard and objective in the first level, you shouldn't have the Colossus yet on that stage, if i'm right it's an undiscovered bug. If it's the fourth level maybe you confusing the names and achievements. But if it is a bug please use their bug report system they really do want to...
Just played HoG last night, only past the first mission.
I am loving all the tweeks and balance changes. So shiny with polish! I very much enjoyed the wizard banter and the incredible amount of unit and Mal lines.
So good guys! So eviliy good, highest praises so far.
By the way, great presentation of you idea.
Edit. You could get round it by having them like (sc2 not Broodwar) nydus tunnels they 'load' in, temporally removed from the map, and are 'unloaded' the other side(s) of your choosing
Could have serious pathfinding issues since we use a flag for all minions, they move at different speeds so we cannot tell the ones who get there first to hold position until everyone is through. Still if that were overcome some fun maps to be made.