Towers Need Upgrades
Games are most fun when you can formulate a strategy, test it out, and adjust it to dominate. Use the powerful elemental system to create awesome combos.
Upgrade towers to counter those mollusk-y invaders. You will choose from tons of different towers, all which have strengths as well as weaknesses. The combinations are endless!
Some upgrades will make the weapon stronger or faster. Others can add entirely new effects! It's up to you to use them effectively.