I set out to make robotron but it kind of changed into something else along the way.
This is a game which I made to demonstrate object oriented programming to some high school students.
  
You are surrounded by zombies and you need to make your way to the exit.
The zombies will always move toward you.  

The game can be played either in turn based mode or real-time mode.
in turn based mode the zombies will get to move after you've made x moves, where x decreases as the game level 
increases.  In real time mode the zombies move reguardless of your movement and they're speed is set by a delay that
decreases as the level increases.

After reaching the exit you can use money to buy ammo for your weapons.  You can also buy an extra life (if you've
saved up enough) and running shoes.  Running shoes allow you move two spaces at a time and allow for diagonal 
movement.

Like robotron you can move in one direction and fire in another at the same time.

Initially the game had two weapons, a gun which fires bullets up to 5 spaces, and landmine which will be plopped 
down on the ground and when something steps on it, anything within 5 units of it explodes (including the player)

It's more cost effective to try to take out the zombies with landmines than with bullets, so use the kiting 
technique (if you've played MMO's you should know this) to round them up and blast them.

During the presentation I created a third weapon in the game, a rifle, which is just like a gun but with an unlimited
range.  This was supposed to be the demonstration of why object oriented programming is so awesome, that you can
add a new gun to the game in a matter of minutes by changing the gun class into a parent class and having a pistol
and a rifle inherit from it.