I am writing another idea separately because it is not related to the previous one. According to the game, it is unclear whether the heroine is a virgin or not. I think this is a very important detail that needs to be identified. I think she needs to be made a virgin. However, at the same time, you will also have to make a special animation for each opponent, and a monologue of the character.
But if you don't make her a virgin, you'll have to add her boyfriend to the plot. Who has either already become a zombie, or protects the heroine at the cost of his "life". For example, when opening the door at school. That is, yes, we will have to add drama and dialogues. Or link her to a teacher who gives her a gun. I am sure connoisseurs of such relationships will be found and appreciated. And again, the drama is in the plot.
By the way! When I tried to pass the boss, I thought that I had missed the cartridges somewhere and returned right to the very beginning. And I noticed that the teacher disappears without a trace. What if we make him some kind of secret mini boss? When defeating which the player receives additional ammunition or even a second gun.
The second option I think is better. Because after receiving the rifle, the opponents become stronger and stronger, and the gun is no longer effective against them. And if there are two of them, it will greatly help the player, and in this case, the consumption of pistol cartridges is doubled. So after getting the second one, paired stores should spawn on the levels