So I'm trying to make a top-down zombie game in a similar vein to COD Zombies. I was wondering if anyone knew how I would implement a round system using this engine? I would like to be able to spawn multiple zombies depending on the round and I could think of an equation to get the number of zombies I want to spawn in, I'm just not sure how I should go about implementing it. I'm pretty new to game development and I've only recently started using this program, so if anyone could help me, it would be very appreciated.