I like the sound of that.
You could even make extra paths open up for different difficulties, or perhaps entirely new NPC’s:
You scramble into the darkness of the alley, desperate to escape the outstretched arms of the zombies behind you. Leaping over crates rotten from dampness, you come face to face with
(if you chose easy) A bulky man, rifle in hand. He looks past your shoulder and gives you a nod. You dash behind him as he shot down the incoming horde, kicking crates in the way of any that remain alive(?).
(if you chose medium) A young woman, eyeing you with vigilance. You note that she has a suspicious gash across her thigh. She holds a short pistol with pale, shivering hands.
(if you chose difficult) A rusty iron barred door, likely a hideout. A piece of metal slides open, a pair of eyes peered out. Focusing on you and the horde behind, the person shuts the piece, and you hear the door locking.
If the people were given skill specialization, like charisma, strength, agility etc. There could be probabilities for the choices to work, so they could fluctuate based on the difficulty chosen. Continuing with the scene above:
(if you chose easy)
[Join him in beating back the impending horde] (has X[low, dependent on stats] chance to get scratched, will raise relationship with the man or something)
[Wait until he’s done, then give him your thanks] (No risk, no reward)
(if you chose medium)
[Console the woman, and explain that you need the pistol to fight off the zombies] (has X[medium] chance to work depending on charisma/speaking.)
[Forcefully wrestle the pistol from her hands] (Once again, dependent on Strength stat)
[Take her hand and run] (Speed, Strength, dependent on author)
(if you chose difficult)
[Pound on the door, begging to be let in]
[Look for a weapon to beat off the zombies]
Even different item interactions could work as well:
(easy) You take the pistol in hand, and notice a full chamber. The woman hands you a handful of bullets, resigned.
(medium) You take the pistol in hand, and notice a full chamber. The woman explains that those are the last bullets.
(hard) You take the pistol in hand, only to be dismayed that there’s one, single bullet inside.
Anyway, I’m just throwing ideas around here, but I really do like the difficulty change idea.