I'm curious about the way you handle zombies spawning.
I never managed to understand how it worked.
Viewing post in Ghosts'n'Goblins Amiga AGA demo comments
Zombie spawn is not 100 % perfect, obviously it is only an approximation resulting from observation of the arcade game. However it is quite simple, against a random number I make either a zombie appear entering from the right side of the screen or the left side, or a zombie emerges from the ground in front of the player or behind in a certain range of distance from the player.