Atreides: Easy win
While playing as Atreides, try to take advantage of
your tanks. They can help not only your defense, but your offense.
For example, if you attack a base with two entrances, create three
or four groups (one of men with typical guns, one of Troopers,
one with slow but Heavy Attack Tanks, and one with fast moving
Trikes or Quads. If planned correctly, this will insure a win
even on the most difficult level.
Strategy guides from GameFAQs