When starting a new game (without closing the window), the new game starts with the old character set and build, which leads to being pretty overpowered in the first rounds on the new game.
The game would be a bit more interesting in the later rounds, if there was some sort of scaling. I like the "merging" (or stacking), but all characters cost the same amount of Gold... Maybe it would be an idea to sell characters of lvl.2, but make them cost more or balance the game more by increasing the prize for dwarfs or spies.
All in all its a really nice little game!