Ya dune2 is dos based. Once you get used to it, though, it'll be very enjoyable. You can't rely on the Fremen unless you have 5+castles and send them all at once. Watch out or you'll run out of spice and won't be able to repair your missile launchers.
Use the keyboard shortcuts. A attack. M move. (Muscle memory)
Also, use the missile launcher. stay away from missle turret range, and fire one square away from missile tower. Enough missiles miss target, land on turret, that with enough missile launchers you can defeat missile turrets, or bleed enemy spice reserves at least.
Protect your missile launchers with a line of heavy tanks just behind, in case the enemy makes a sortie.
(Ohhh, I have to play it again now... See what you've done!)