Game is done, I learned a lot. The spawn engine is the best one I've made, it's based on Killing Floor 2. The main thing is the simple design. It makes it easy to place enemies and swap them around and the spawn rates are simple to adjust. And it works up to 5 players. It needs more, like auto balance player vs enemy. It needs re scripting because I have low skill, but the basic idea is correct.
I also learned vampire magic, where landing the killing blow gives a small heal. It's awesome in combat, when it's on the brink and you make a few good dodges to heal, rally and win. It is a compelling thing when coupled with some sort of loss upon death, but a difficult balance, hence the auto-balance idea. That will be the next game, probably a gladiator type game with waves of enemies, like leopards and guys with spears in an arena, just to refine the spawn engine some more.
PS I was formerly XXon