It's already basically a zombie RPG w/roguelike qualities, so maybe the sequel (or remake) would be better if you just took it in that direction and fleshed it out more. Different weapons and armor would having different Attack and Defense ratings, respectively. Training would increase maximum HP. Killing zombies would yield EXP, which could either lead to level-ups or be spent on increasing stats or learning skills. Using Medkits would increase your skill with them, such that future uses would recover more HP - much like using bullets in battle would increase accuracy, damage, and/or critical hit rate with guns.
There should definitely be different choices available for each event. There were just too many events with no choice on the player's part, and a lot of them ended up giving some kind of penalty (e.g., the bandit encounter damages you, the boot/plank misstep thing damages you, the super zombie either damages you or makes you lose resources). Also, there were waaaay too many super zombie encounters in my playthrough past day 200, making it impossible to stock up on bullets or medkits.