I'm not sure how that would work for an on-rails shooter (maybe the player doesn't move?) but it is something I am open to adding in the future as a lot of people have asked for it before.
I have suggestion- The player could move, There would be weapons which the player have to purchase. There will be points, more zombies u kill, more points ans from those coins players can purchase. Zombies will come rushing, it will get harder and harder👍🏼
