If you haven't played Independence War recently, go through the original game's training
missions to get acquainted with the ship's systems--the difficulty of the Defiance
campaign ramps up immediately.
You can change your PBC (particle beam cannon) orientation mid-mission by going to the
ARM screen.
In most missions, you'll want to save your missiles for later encounters. Stick to your
PBCs until you're overwhelmed by superior numbers.
Some of the missions have branching paths. Restore to an earlier save point to explore
the alternate path if you're having trouble finishing the mission, or if you want to try
for a higher mission score.