Need help in GE (Death and how many bullets it takes)

Basically I have made a basic zombie game with AI bots. I have it so that the bots <in collision with bullet> end object (bots) which works fine. I would like to make it that its in collision with 10 bullets or 5 bullets it kills them, at the moment it only takes one which is far too easy. Any help would be much appreciated.

Basically I want to know how to kill an enemy in 10 bullets not one.

Also my game lags if have too many zombies at once so is there a way to make it so when I kill 1 zombie, another one spawns? Thanks.

Concerning your first question:

you could do that with logic bricks. Give your zombies an integer property, called “hitpoints”, and set it your desired amount of hitpoints.
Give them another boolean property called “alive”, and set it to true.

<in collision with bullet> -> <decrease hp by one>
<if hp in range -something* to 0> -> <set alive to False>
<if alive = False> -> <end object>

*if you plan on dealing more than 1 damage at once, you may need to set a high enough range, so that your zombies are still killed when they have negative hp.

Concerning your second question:

There is an “edit object”->“add object”-actuator.
You could connect that logic brick to the “and” controller of your <if alive = False> sensor.
Should you however wish to change the spawning position, you might want to use a python script for that.

Thank you, I tried this but I didn’t understand exactly what to do (Im new-ish to blender) so I am going to PM you the .blend file. Thank you.