How do you complete the achievement 'Artillery Mastery' for the Osprey?

Question

It says 'Get to Sector 5 without upgrading your weapons system'.

The Osprey has two weapons systems, one for standard weapons and one for a special beam weapon it has. Am I restricted from upgrading one, the other, or both?

Answer 1

You can freely upgrade the artillery system but not the standard weapon control system (the weapon system is the one that gives you more power to use for standard weapons like lasers, missiles, etc).