So you can only perform one regular action per activation, however, charge is a sub-action (one you can perform after a main action) and discharge is a main action. I feel like the optimal choice is to charge twice than discharge afterward but I feel like the rules prevent this. Am I missing something? Did I read the rules wrong?

It prevents a solo marine from using two main actions in a turn if they wish to use discharge, but doesn't restrict your bonus actions is how I look at it.

Read through the rules again. I read them wrong. I understand now, my bad.

And as it turns out, Discharge really freakin' hurts.

Pairs well with chaingun.

Charge, charge, discharge is one of my least favorite things to see played as the invader.

Charge, charge, discharge is one of my least favorite things to see played as the invader.

Alongside the combo that the chaingun gives, right? Right?