The freezer module manipulates the movement of the beasts negatively.
The poisener module deals poison damage per second to effected beasts.
The damager just increases the damage of your tower.
The crity will add highly critical damage values on your bullets. They will deal a lot of damage.
The aoety is a area of effect damage that spawns with the bulletimpact by chance.
The stunner module manipulate the movement of the beasts and forces them to stop.
The burner module deals burn damage per second to effected beasts.
The holy module manipulates the movement of the beasts and send them back to the spawner.