Since I've noticed this thread, I've been wondering: are you looking for a subtitles script proofreader?
Also, a few things bother me in the translation, hope you wouldn't mind me sharing them?
EDIT: Ah, what the hell.
Mind you, I'm working on an ancient version of the files:
Minigunner - Strzelec (fizylier is an antiquated term, jarring when used in context of GDI).
Bazooka - Rakietowiec (common name for a soldier serving in Rocket Artillery)
Flamethrower infantry - Miotacz ognia (Miotacz ognia is a noun that can both refer to a flamethrower and its operator; Ogniomistrz is also an artillery serviceman rank's that doesn't have anything to do with flames)
Chemical warrior - Miotacz chemii
Watchtower - Strażnica (again, Baszta is a VERY antiquated term)
Also, consistency is important. If I recall correctly Polish grammar rules, you don't translate codenames etc., which means Apache and ORCA shouldn't be translated.
Also, have you considered translating APC as simply BWP (Bojowy Wóz Piechoty)? Granted, the M113 isn't an actual IFV, but it could look a bit prettier.