Enemy wave Control

Roksalt

Hi I'm creating a game similar to "Zombie Smash" or "Knights Onrush" and I'm wondering the best way to implement an enemy wave system similar to the ones used in these games.

I know I can create a simple system that spawns slightly more enemies each time based on an attribute but I really want more than that.

I would like it to have a slight bit of randomness to it and allow for multiple enemy classes as well as the game getting progressively harder...

Any samples, tutorials, advice would be great.


Thanks in advance

Roksalt

***Update***

I purchased tshirtbooth's P vs Z template and saw how he did wave control. Its very nice so I have decided I will go with that method.

Thanks anyway!