The developer must be aware of how broken the archer upgrade tower is. This game is fun through the early levels, but once you have the gold to buy about 9 archer upgrade aura towers, there is nothing that can stop you.
The problem is that the upgrades stack instead of making a small difference. After about 9 or 10 of these towers your archers are firing an infinite number of shots each second, so you instantly kill anything that comes within its range.
This game could be really great, but it needs work.
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