towerLevel

The Upgrade class handles a specific tower upgrade's stats. An upgrade consists of 0 or more modules. In contrast, the Tower class handles all stats of a particular tower configuration. To illustrate the difference between these two, here are both instances for a Monkey Wizard's Intense Magic:

Upgrade

• magic-bolt buffed
  • +5p (8p)

Tower

• magic-bolt attack
  • 1d, 8p, 1.1s, energy type

As you can see, Upgrade is for how stats modify a tower, and Tower is for the entire tower's stats with a certain arrangement of upgrades. Tower works by iterating through all the upgrades and applying the stats to the tower.