Money (bounty) is awarded for kills and interest is earned on the money left in the bank at the end of a level. Money can be used to upgrade the base in various ways. Beware: an upgrade to one aspect will degrade another!

Current interest rate and bank balance are shown under the score in the top left of the screen. Current level and lives left are shown in the top right.

The Base

Tap the screen to move your base. Use diectional pad to tweek position. Movement speed is determined by the 'speed' attribute

Cloak

Activating cloak will allow you to cross a wave undetected and at twice the speed to help you get into the perfect position. However, you will not fire while cloaked.

Attributes

The base has a number of attributes, listed below. Upgrading one attribute may degrade another, so plan you upgrade path to suit your play style.

Damage - The amount of damage caused each hit. Upgrade affects: Speed.

Rate - The waiting time between firing. Upgrade affects: Range.

Chain - The number of enemies hit per shot. Upgrade affects: Damage and Rate.

Speed - The speed the base moves. Upgrade affects: Damage.

Range - The range of the bases fire. Upgrade affects: Rate.

Powers

Powers are listed to the bottom of the screen. With each clean round, the power level increases.

Any power below the current power level can be selected, but only one can be active at any one time.

SCR (Score) - The score from enemies is increased.

RNG (Range) - Tower range is increased.

MNY (Money) - The bounty from enemies is increased.

DAM (Damage) - Tower damage is increased.

BOM (Bomb) - All enemies explode!

Bonuses

A special enemy that releases a bonus is available every 8th level. The bonus is awarded automatically.

Reward - Receive a score and money bonus.

Interest - Interest rate is increased.

Lives - Gain extra lives.

Additionally, extra lives are awarded at 50,000 points, 100,000 points and every addition 100,000 points scored.