First 25 in a combo = 10 gold, second 25 = 15 gold. So, first 50 = 25 gold. Then from 50-100 = only 20 gold. Best to reset your combo after 50: get more gold that way.
The game engine works well, but the details are extremely unbalanced. The campaign is very easy, and there is never really a need for strategy and planning.
Energy maxes out too quickly, the "floodlight perimeter" strategy is far too easy to implement.
Great start, but needs balancing.
We originally added the Arena as a late game item to make you spend your Soulons. But we realize it was obviously not enough :)