How can the Full Arsenal achievement in FTL be achieved?
Anything that's labeled as a system or subsystem in the upgrade screen.
8 systems, 4 subsystems. Before the expansion, there was only 3 subsystems (no battery pack) and only 3 available systems to add (cloaking/drones/teleporter, no mind control/hacking)
Full Arsenal requires 8 systems (rooms which require power) and 3 subsystems (rooms which don't- the Kestral already has three).
You already begin with five systems and three subsystems, so you need three of the following:
- Teleporter
- Drone Bay
- Mind Control
- Hacking
- Cloaking