Switchable Archer Tower mode of attack.
The mode works similar to Xbow's ground or air+ground attack setup.
There will be 3 types of attacks, Flame Archer Tower, Poison Archer Tower and the Normal Archer tower
Flame will do 25% less damage than Normal, but it has aoe splash damage (probably 1 tile or 1/2 tile splash).
Poison will do 10% more damage than Normal, but its attacks are DoT (damage over time) base and slows target by 10% movement speed.
Normal will do the same old damage but get a slight 5% increase in attack speed.
well the numbers and figures can be readjusted and balance out, but let me know how does the general idea works out. thanks.