The Zombie Alchemy

Our main character will be a young 20yo boy name Raju he'll be fighting a mad scientist in his village:

our story will start with there was a mad scientist in a village he was really greedy for powers and wanted to be the strongest in the village so he created a dose to convert himself into a beast and created another dose for the villagers. He mixed that dose into the well ( every villager drinks water and uses that water for their daily use) and now they have consumed that dose and every villager has totally converted into a zombie but there would be a group of people who are immune to this dosage, can be used as slaves for the scientist and then raju the main character sees this as injustice and fights against it. So our player will be fighting the zombies in the first half and in the 2nd half he'll fight the mad scientist who converted himself into a beast.