Researches are organised in linear paths with no prerequisites between branches. Once a research is done, the next ones become available.
The deeper a research is in a branch, the more it costs to research.
Each weapon class has it's own research path, which starts with the tier 1 turret. Once the tier 1 is available, the next tier becomes researchable and the upgrade branch opens. Each class has 3 upgrades that increase its rate of fire by roughly 11% each.
Researching a weapon will unlock the tower or emplacement according to the weapon type. To unlock bunkers you must research Hardcrete wall.
Each weapon research costs 300, 450 and 600 for each class. The upgrades cost 200, 300 and 400.
The sensor path starts with the regular radar.
A radar turret has a long line of sight. You can assign artillery units to it to share it's attack order and automatically target units that are detected by the radar. Non assigned units will automatically attack only within their own line of sight but can still be manually asked to fire further as long as an ally has the target in sight.
Artillery emplacements must be built near a sensor turret to be able to fire at full range, as they cannot be ordered manually.
Wide spectrum sensor has a longer range and can order counter battery fire even if the artillery is out of sight.
At the end of the path, the laser satellite command can order a satellite strike anywhere on the map every 2 minutes.
Sensor research costs 200, wide spectrum costs 300 and laser satellite command post costs 400.
The repair path is composed of the light and heavy repair turrets, and finally the auto-repair ability.
The vehicle body path starts with medium bodies and Nexus small body. Large bodies become researchable once the medium bodies are researched.
Armour upgrades can be researched after medium bodies are researched. Each of the three upgrades provide +8% body HP to your units.
The structure path starts with the hardcrete wall, which will automatically unlocks bunkers once the weapon is researched. Next are the 4 HP upgrades which gives a +25% HP bonus for all your buildings.