Parameters

This Japanese game is the first of two where the ultimate goal is to defend the city against alien invasion. This is done by upgrading a number of skills and attacking invaded territories/occupying abandoned territories. Once completed, the game presents the player with a total play time.

Occupying/Attacking Territories
Land is gained by occupying squares. Free squares are those with a black background and a % number on them. With each click, the % will increase and a small amount of cash and xp will drop. Cash can be spent on unlocking locked squares or buying upgrades on the map, while xp is automatically applied to the player's current total.
Attacking yellow squares requires the strength of the player's army to be sufficient enough to eliminate the alien threat. With each attack, the player's defenses are attacked in turn, either resulting in the player being "injured" or "killed". If the player is killed, they must wait for their health to rise again before attacking again, during which time, the alien forces can return to the square in question. Once a square has been defeated, it becomes open to occupy.

Cash
Cash is rewarded with each time an unoccupied territory is clicked, and a smaller amount when an occupied territory is clicked. Cash can be spent on buying upgrades on the map, that affect a few different aspects of the game such as attack strength and life recovery.

Levelling
This is done automatically when the player collects enough XP. Once a level has been achieved, the player receives points that can be spent on attributes. The attributes are assigned at the top of the screen using the + buttons next to the three lines. The three available are Recovery, Attack, and Defense.

Action Points
Actions can only be performed when the player has enough points to spend on performing them. These can be seen in the purple bar on the left of the screen. Each action takes a number of points to perform, and these points are returned at a rate determined by the recovery score of the player.

Keys
These are rewarded to the player upon defeating enemies. Keys are used to unlock locked squares on the map. Both silver and gold keys are available to the player, and will only unlock their respective locks. It is important to note that some upgrade squares are locked and require keys to access, adding a level of strategy to the game.