[?]: "Town"

Tried playing. Lots of empty space, endless waves of enemies pouring through numerous portals. Overall, not a great experience...

That's how the map is designed. First, build up your army and head south from the town square. Talk to the mage, and then follow his leads to find the keys. It's better to hire a secondary hero, give them an army, and leave them to guard the town, while the main hero progresses.