Zombie Survival Game (real Life)

You look down the street and see an ocean of undead shambling aimlessly around. You've been quiet and survived this long. You decide it's not safe to be in this area searching for supplies and you should leave town. As you turn to leave you bump a garbage can and to your horror a bottle that was sitting on it begins rocking back and forth. It looks like its just about to stop when it takes a bad wobble and losses its balance tipping to the ground with an ear shattering smash. All the scratched, foggy unblinking eyes in the area turn to you and your escape route fills with cold walking bodies. At the last second you see an ally and sprint down it but like from a bad dream it's a dead end. You turn to leave but before you can the only way out of the ally is full of zombies grasping for you moaning and snapping there teeth. The only thing to do is stand and fight.
How long will you survive.

Now that you have the gripping tale of your inevitable
Doom let me explain the game.

The game is a basic tower defence game but instead of being played on a computer you play it in real life. It can be played with any number of players and can easily be adapted to many activities from shooting and archery to sports. Me and my friend invented it while fooling around with throwing knives, that is the version I will use to explain the game.

CONCEPT:

ZOMBIES:in our game the concept is, there is a zombie walking towards you. The zombie is able to take a certain amount of steps each turn trying to close the gap to get to you. The zombie A.K.A your target doesn't actually move its just a score to see when the zombie would reach you and you are eaten or in other words have lost the game.
The the game is played in turns, each set of throws equals a turn, we called them nights as in the passing of a night you survived. And each round the zombie can take more steps getting more and more difficult.

PLAYERS: we had seven throwing knives. So we said the zombie had to take seven steps to reach the player. To keep a zombie away from you you had to stick a knife into the target "knocking back the zombie". Keeping him at 7 steps away, A zombie can't go farther than 7 steps away, or you had to land one kill shot. This meant hitting a bullseye. We had drawn eyes as our bullseye. So basically you have to land at least as many hits equal to the amount of steps the zombie would take.

SURVIVAL: say on night 1 you said the zombie takes three steps. This would mean you must land three of your seven hits or 1 kill shot to keep the zombie seven steps back. If you only landed 2 the zombie would now be 6 steps away from you on your next turn. The tricky part is on your next turn its night 2 and the zombie takes 4 steps so it gets more desperate. This is also what makes it tower defence.

A lot of writing for a simple concept.

Some later rules that we added added the idea of finding "supplies" or "single use items."

For example:
If you scored 7 hits in a single turn you would find an "additional knife", not actually but it gave you a one time use mulligan.

2 kill shots in a row got you a "good luck charm". You choose a turn and for that one turn your knives count for 2 hits each

3 kill shots in a row and you get the "hand gun". If a zombie reaches you you draw your trusty pistol and shoot him knocking him back 2 steps. This can only be used at the moment you should have lost.

My wife has no interest in throwing knives but we do play basketball together. She likes the game idea so we adapted it for practicing free throws. The game is the exact same but a baskets knocks the zombies back a step and a swish is a kill.

Adapt it to what you do and tell me about it and please share your ideas to add more interesting rules or just make it better. Thanks to those of you the read through this.