Hardpoint: Range Enhancer (Level 1)
Unlocks the Range Enhancer module for the Walker. Choosing it allows you to increase the range of all weapons and some components. I'd strongly recommend unlocking this level of the branch.
Hardpoint: Arc Turret (Level 1)
Unlocks the Arc Turret module for the Walker. This is an offensive component. Arc Turret are being used to attack enemy air units. It's very good to have them, especially if you don't want to build saucers.
Plasma Weapons (Level 1)
Lost One units are capable of using plasma bombs and Grunt units can start using plasma grenades. These objects aren't too powerful, so you may as well ignore this achievement completely.
Call Hero: Orlok the Eternal (Level 2)
I'm sure that you remember Orlok from the second campaign of the game. You should exactly know what to expect of him. He is a very useful character and it would be a mistake not to hire him.
Death From Above (Level 2)
This technology unlocks a new ability for your Brute units. They can damage targets while performing jumps. You should be interested only if you like using these creatures. Otherwise ignore this bonus.
Foo Longevity (Level 2)
An excellent technology, especially if you like healing your units and Walkers. Your flying saucers can withstand more damage and the effectiveness of using Repair Chambers is increased.
Hardpoint: Mass Driver (Level 3)
Unlocks the Mass Driver module for the Walker. This component increases the damage done to enemy structures.
Hardpoint: Visual Optimizer (Level 3)
Unlocks the Visual Optimizer module for the Walker. As a result, your line of sight is increased. The only advantage is that you can place these objects on a Science Walker in order to reveal the entire map.
Hardpoint: Beam Cannon (Level 4)
Unlocks the Beam Cannon module for the Walker. This weapon can be mounted only on Assembly Walker units. It's very powerful, so you should decide to purchase it.
Locomotor Enhancement (Level 4)
A very interesting invention which I'm sure you'll find to be useful. The movement speed of your Walkers is increased by 60%(!!). Buy it at all costs if you're using these units during the attacks.
Volatile Reactors (Level 1)
I personally didn't find this technology to be useful to me. Destroyed Walkers and vehicles can now explode. Additionally, they create a poisonous cloud around them.
Irradiated Shots (Level 1)
This technology is very useful. Your units can now fire irradiated projectiles to inflict more damage to enemy troops and vehicles. I'm sure that you will notice the difference once you've started using it.
Call Hero: Nufai (Level 2)
This hero is often being used by AI opponents, however I prefer hiring other Hierarchy heroes. You can try him out if you want to, but don't expect him to be a big help.
Hardpoint: Brute Pod (Level 2)
Unlocks the Brute Pod module for the Walker. It's simple - you can now attach these pods to your Walkers in order to summon Brute units.
Hardpoint: Radiator Artillery (Level 2)
Unlocks the Radiator Artillery module for the Walker. This component can only be mounted on Habitat Walkers. Obviously it uses the effect or radiation.
Gamma Radiation (Level 3)
Interesting achievement. Unlocking this technology allows you to increase the negative effects coming from radiation by 50%. Additionally, radiation heals your units more rapidly.
Advanced Mutagens (Level 3)
This technology allows you to unlock a bonus that's very similar to one of the main abilities of Defiler units. Civilians and smaller enemy units can now be turned into mindless Slaves.
Hardpoint: Radiation Cascade (Level 4)
Unlocks the Radiation Cascade module for the Walker. This is BY FAR the most interesting option of this branch of the technology tree. These hardpoints allow you to use the main attack of Science Walkers.
Phase Modules (Level 1)
Unlocking this technology allows your Lost One and Monolith units to use Phase Self ability. Not useful. You were able to test this feature during the course of the second campaign.
Mental Frequency (Level 1)
This is also an achievement you can ignore. Mental Frequency allows you to neutralize all negative technologies being used by your enemies to take control over your troops.
Call Hero: Kamal Re'x (Level 2)
Kamal Re'x has appeared often during the course of the game, however you weren't able to control him back then. He's a pretty useful character and you should consider hiring him.
Hardpoint: Phase Tank Pod (Level 2)
Unlocks the Phase Tank Pod module for the Walker. I think you won't have any problems understanding this achievement - you can start building Phase Tanks.
Fast Ordering (Level 2)
This technology isn't something you would want to have at all costs. Units summoned by your Glyph Carver appear on the map 25% faster. Nothing else.
Quantum Ordnance (Level 3)
An interesting achievement. This technology increases the damage done by your plasma weapons by 20%. Can be quite useful, especially if you have these weapons mounted on your Walkers.
Molecular Armor (Level 3)
This is also a very useful technology. It puts a better armor on all hardpoints of your Walkers. As a result, enemy troops will have more problems destroying your mech units.
Hardpoint: Targetting Jammer (Level 4)
Unlocks the Targetting Jammer module for the Walker. This upgrade can only be used by Science Walkers and it makes them harder to being targetted.
Hardpoints: Mind Magnet and Machine Magnet (Level 4)
Unlocks the Mind and Machine Magnet modules for the Walker. They're very useful, because they can allow you to take control over enemy troops and vehicles. Definitely worth a try!