Your steps change the game.

The phone counts, you walk

Zombie Hikers reads the steps your phone is already counting. Nothing to open, no screen to keep lit, no button to press on your way out the door. You head to work, take the dog out or go around the block after lunch, and all of it is saved.

And they don't have to be counted by the phone: if you wear a fitness band or a smartwatch, that works too. As long as those steps end up in the phone's record, the app runs just the same.

There's no GPS here. The game doesn't know where you've been and doesn't want to: only how far you've walked. That dot you see moving across the map isn't you — it's your character, and it walks a map invented for the game, not a real place.

The step bag

Everything you walk drops into a bag. That bag is the only thing that moves your character: no steps, no going anywhere, end of story.

Where they go

Steps are spent on one thing only: moving around the map. A step from your bag is a step for your character, and getting from one place to another costs whatever that stretch measures.

Searching a house, picking something up or looking around costs no steps. What cost you is having got there.

That's why the call is never “what do I spend it on”, but where do I go and which way:

• The short way. Fewer steps, but it goes where it goes.
• The detour. When you see hordes on the short route, the game offers you other ways around, of each one it tells you what it costs in steps, how long you'll take and how many hordes are in sight along it, so you compare with the same figures in hand. There's no cap: however dear the detour comes out, you're still offered it and you decide.
• Staying put. Costs you nothing. But thirst and hunger keep dropping.

A step in the bag is a step forward. Going from one village to the next costs whatever the stretch says, the same for everyone; what changes between characters is the pace, meaning how long you take.

And there's one more way out, this one on purpose: you can drop steps on the ground as if they were an item, for another player to pick up. It's the only way to hand somebody a bag.

Thirst and hunger: the clock that never stops

Both bars go down with the clock, not with your steps. Doesn't matter whether you're walking, standing still or hidden: hiding protects you from zombies, not from hunger.

• If one hits zero, the tiredness starts to tell: the pace drops and the hands shake. He can't defend himself the same —shooting or up close—, he starts missing, and in front of a horde that costs you dear.
• If both hit zero, you die. No warning and no fight. It's one of the two ways to die in this game.

That's why searching places isn't optional. Every item says what it does and almost none of them are free: the cold-cut sandwich kills the hunger on the spot, but it leaves you parched.

What fits in the backpack

Not everything fits, and what does depends on who you pick:

An item takes a slot: two bottles of water are two slots. On top of the backpack you have two hands for equipped weapons, and those don't take up room.

You play it in the dead time

You don't have to sit down to play. You open the game in the supermarket line, see where you are, decide your next move and close it. Your character keeps going on the steps you gave them.

And if you don't open the app for two days, the world doesn't wait for you: the hordes will have moved and the shelter you were heading for may not be yours anymore.