I can't seem to get Area 4 unlocked. I've earned the key and placed the station next to the floating key and an associated train to go from city 3 to area 4 station, but no luck.
This is a great game. It would be even greater if the heroes earned experience after completing a mission, but as is, I've been coming back every day now for at least a week. 5/5
How about a display showing the stats of the killing blow. Like the elemental, the type of enemy: normal, assassin, boss, etc, range, attack points, enemies remaining hitpoints, etc... I would find it useful, when going back to town to buy more permanent upgrades.
As soon as you build/buy 100 land, the mine is unlocked and the resource accumulation explodes. Max out the number of collecting souls and you'll start to see some real buildup.
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