Mission 03:
You need at least 4 vehicles with gun (and 1 radar, hovercraft). You must attack from left and kill repairing engineers (first kill gun engineer, then destroy gun turret, then kill gatling gun engineer and destroy turret).
If you have an ally with Americans, its easier (you can attack with them together). But if not, its intermediate - hard.
To get ally with Americans, select in first question first selection, and in second question select crates. After some minutes Americans will ally with you.
In next version i'll make it little bit easier, its rly difficult.
Mission 08:
In factory you must build a remote rocket launchers (i think that max. is probably 4-5, because there are so close no crates). Every wave you must plant remote mines (if you can). Then boom them and change soldiers to mortars.
I always had 2 people in north barracks and 2 in south barracks (+1 engineer to both). I'll draw tomorow a tutorial image.
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edit: A nawet jak się przejdzie 8. misję, to jest ten błąd (przynajmniej u mnie):
You mean when you complete 8 mission? never got that :/ but I'll check it