Modifiers

At the beginning of a playthrough, an assortment of 7 to 9 modifiers are chosen at random. Before the start of each wave, +10% of a modifier is added. In addition, before Wave 1 and every 5 waves after, a modifier that remains at 0% or is already negative will also be deducted by -10%.

Many modifiers can be either plus ( + ) or minus ( - ), but most are exclusively one.