Dragon Rising had a steep learning curve (for me anyway), with enemies who liked to hide in thick foliage and objectives that if failed could end your game prematurely. The night time, stealth missions frequently come to mind. Also it was a bit jarring given that you cycled between different characters in different units each mission. While this opened up the variety of missions you could do, you never really got to know who you or your guys were, or why you were doing silly things like capturing a village on the far side of the map.
Red River fixes most of that and is basically a more polished and more user friendly game. As a marine grunt most of your sorties are all out strategic adrenaline pumping firefights - just the type I like but most importantly it also gives an easier to follow story. While your overall general sounds like a bit of a douche during the mission briefing screens, the true star of the piece is Staff Sgt. Knox who is out on the field with you giving you tips, assessing your performance and generally telling you how it is with often funny foul language.