Beta: Shield Breaker (1 SP), and finish one Beta line before starting another.
Learn skills at camps and try them in training mode first. SP comes from kills and searching bodies.
3. Skills that unlock later
Burst: beat Stalker in Matrix 11 (Alpha Signal). Fill it with perfect parries/dodges, Blink and Repulse.
Tachy Mode: the Hidden Truth quest after Alpha Signal. L3+R3; Beta and Burst do not build while it is on.
4. Cores
3 Body Cores = more max HP; 3 Beta Cores = more max Beta energy. Applied automatically.
They come from Airborne Squad bodies and merchants, so search every body you pass.
3 Tumbler Expansion Modules add a healing charge. Cans raise your consumable limit.
5. Exospines and Gear
One Exospine at a time. Reflex-Type (easier perfect parry and dodge) is the usual early pick.
Others include Beta Trance, Burst Trance and Protection (-10% damage taken).
Gear starts with 1 slot and expands to 4; Combat Supply, Protection, Crit Boost and Beta Charge are safe picks. Upgrade at the Repair Console in supply camps.
6. Difficulty
Story and Normal from the start, changeable any time; Hard unlocks after a clear.