They do seem lifeless, huh. Anyways, it is very action packed, with lots of enemies jumping around at you. In the game, you can wield a weapon in your left and right hand. The left mouse button fires the left hand weapon, and the right mouse button fires the right hand weapon. Targeting is done via the mouse wheel. You scroll it to switch between the enemies on view. You can also manually, but you will be jumping around and dodging so often that it is easier to just swap targets with a quick flick of the wheel.
The fun part is when you get your powers. Powers can be equipped to your hand just like your weapon. Your powers can also unlock a second ability that you can choose between. Your speed power can unlock a time slowdown. Your shield power can unlock a personal shield bubble. You can move a single enemy around with your levitate ability, or lift up multiple enemies and toss them to the side. And more for your other powers.
The game really makes you feel like a powerful demi-god, but you are still very vulnerable to attack. The later game is all about using your abilities to annihilate hoards of enemies will minimizing the damage you take.
A flaw that most people originally touched upon when the game was released is the fact that your powers level up by using them. This is fine in and of itself, but all you need to do is spend a little while spamming your powers into a wall to have them reach max level.
Anyways, it is one of my favorite games, so I would recommend you pick it up. The only thing you have to worry about is the steep-ish system requirements. I remember it chugging a bit on my GeForce 6600 back in the day. Even today, maxing it out chugs my 8800 GTX a bit.