Poor controls ruin what was an awesome game.
As I noticed before reading the GameSpot review, the controls are terrible. It is very difficult to move your cursor around the map in a quick fashion, and the inability to make precise movements kills the castle-building phase of this game. GameSpot's review mirrors this assessment, and I strongly recommend you follow their advice.
The idea of online play is great for Rampart. However, when I went on to look for a game, there were no games to join. This is likely because the people that downloaded it never played it again after experiencing the control issues in the single-player game.
There are much better games to purchase on the Playstation download service. Pass this one by.