## placement of structures
Have a single structure that can be placed on click of the mouse
## add an enemy
Have a single enemy that can attack the player structures
Consider enemy behaviour - movement, attack style, range, etc
## structures can defend against enemies
Need a way to kill the enemy
How does the structure do this?
## multiple defence structure types
Swap the structure that will be placed via a keyboard shortcut
Choose a different shape or graphic per structure
## hud for structure selection
Provide a way to visually show the available structures
Distinct styling for the structure selected for placment
## multiple enemy types
## waves of enemies
## scarcity to prevent infinite building
need a way to control the speed at which structures can be built
idea: initially have resources passivly accumulation over time
idea: need to build bots. bots need to move between a store of resources and structures being built. strategy in not too much placement. distance to travel. etc. upgrade oportunities like speed of bot, number of bots, speed of bot production. bots can be destroyed, so must be protected. hp can be upgraded. upgraded bots take longer to build.
idea: special purpose bots to refill ammunition?
# increase difficulty