Droids at the Gates

Robot armies are attacking your space headquarters. Stop them whatever it costs.
Protect the HQ Gate by gate installing turrets, catapults and barricades in their way.
Use your resources cleverly, or you’ll run out of your budget fast.

TURRETS
Your primary class of weapons are laser and plasma turrets.
They can lock on targets from a great distance, and shoot accurately til the attackers drop dead.
To build a new turret click turret icon and choose the any type of turret that you want: laser, plasma, EEMP800 or EEMP1000 turret. Then place your turret to the valid green area near the base.
Upgrade your turret to make it more efficient. Their fire rate, damage and shooting distance can be upgraded in 125 different ways.

CATAPULTS
The second line of weapons are catapults. They don't lock on targets.
They shoot blindly and constantly to the specified area damaging everything in the given radius.
You have access to the next types of catapults: basic, enhanced, bouncer bullet and the XV1000 monster catapult. Their fire rate, damage, explosion radius, shooting distance (range) and fire spread can be upgraded in 1875 different ways.

BARRICADES
You can delay and damage the enemy placing barricades in their way.
Normal barricades.
It takes time for the robots to avoid or to eliminate them so your weapons have more time to destroy them. Types available: basic barricade, enforced basic barricade, medium barricade and strong barricade.
Explosive barricades.
These types self-destruct on contacting the robots. The white ones also contain a 'surprise'.
Types available: explosive trap, explosive trap v2.0, fragmentation bomb, fragmentation bomb v2.0.

BASE UPGRADES
Shield: Decreases the damage caused by enemy bullets.
Weapon Area: Extends your area so you can place more weapons.
Recycle: Increases the money you gain after killing an attacker.
Auto Repair: You can gain back energy units as time passes.
Energy Pool: Extends the maximum possible energy level of your base.