I found the game to be difficult from two reasons. First, the graphics. Second, the mechanics. A real time strategy game is just too fast paced to be played with a control pad. If you are going to effectively play this one, I recommend that you get the mouse to play this one. It's near impossible otherwise.
The game itself is challenging, but not difficult. It's definitely doable. If you are a fan of the Command and Conquer series, this should be no problem for you. It takes a quick hand and a fast mind to stay on top of things, but overall, it's not too bad.