Age Of War 2

You begin with a selection of dinosaurs and catapults at your disposal, and a cave to defend. You are under attack from a similarly equipped foe and you have to winn. You get money for kills, and can use money for upgrades, every now and then shooting up and 'Age' through Roman and Egyptian and the like which affects your troops in type and power.

It's a properly good-looking game and the progression is swift and relentless. There's a fair few references thrown in there too for good measure.

Just use the mouse to make the magic (quite literally in some cases) happen.

Go for the age progression as a priority... this is where the real power is.