If I had one complaint about the Dungeon Siege games it's that they were a bit too automated for their own good; you didn't feel much interaction since the game took care of combat through auto-attacks. That's something that's been rectified with Space Siege, as much of it feels like an action game that requires you to input attack commands manually. Left clicking the mouse will cause you to move, while right clicking the mouse will attack a target. The tricky part is getting used to the camera, which is controlled by the W, A, S, and D keys. A and D rotate the camera, while W and S zoom in or out. This is the kind of game where you always want to move the camera around to better see the action.