Cheat Engine

[mordax]

couldnt find a better title, what im trying to do, is that in some games there's instruction that controls many things. for example health.
in some games if i do this:

search for health (filter ..etc)
find the address, change and/or freeze and make sure its correct
breakpoint it
now i get a breakpoint, if i NOP the instruciton (function)
then as a result, everybody's health in game stops changing, meaning invincible enemys too.
how would i go about seperating it ?

my case is not health tho, its a game where you have inventory slots (like deus ex for example). i have found the inventory slot and i want to do is, is make a script that changes only ONE slot. so if i enable the script, then for example ammo spawns into that slot or if there's a weapon, then i could change its stats with the script.