One additional suggestion for improvement: The descriptions for towers and skills in the Keeperpedia are virtually worthless as is, because they don't describe the different game effects. I have no idea what the skills do, or why I should choose one tower over another in the early levels. If they just have different stats, the whole elemental theme of this game is a sham.
It's a very unpleasant surprise when you're about to beat the mission you've been working on for 30 minutes, then accidentally click "Survival Mode". D'oh!