Everyone loves coins!
The player can no longer gain experience from killing insects. Instead, he will collect coins found throughout the level. This it to encourage exploration and to eliminate an abusive exploit I found while play testing the game.
Basically, if the player wanted, they could just spit 1 fireball at an ant above ground and that ant would cause a chain reaction of fire ants, which would travel across the entire map and grant a nearly unlimited supply of experience. To avoid this, I simply took out experience gain altogether. The player can still kill as many ants as possible with fireballs, but they will not be able to abuse it by gaining too many experience points.
There are a limited number of coins in each level, and not all coins are easy to find. These coins will be saved and used to buy items from merchants hidden throughout the game. The player will eventually be able to buy these coins with real life money if they don't want to farm the coins, but it is never required to do so. I don't want my game to turn into some crazy money making scheme where players with more money can easily just beat the game. I want the challenge to be equally difficult, which is why the merchants will be hidden throughout the game instead of being able to enter a 'shop' from a GUI icon and simply buy all the upgrades outright.
Yes, this will net me far less money in the long term, but the game quality will be better overall. I want this game to be fun, fair, and most importantly, free to play.