This is a massive train with two shotgun-chain-guns mounted on top. A shotgun-chain-gun is a chain gun that fires multiple pellets at once instead of just one. The chain gun is super rapid fire, and it has a lot of ammo to start with.
ARROW KEYS TO MOVE (to run over people), F TO FIRE BOTH GUNS(to blow stuff up), G AND H TO AIM MAIN GUN, I AND K TO AIM SECONDARY GUN
WARNING: Lots of shapes. Only use on a computer that can run Phun easily.
By the way, I think the Windows version of Phun is faster than the Mac version. My computer is about the same speed as the Windows I tested this on, and the Windows version can handle more stuff (and water, which mine can't for some reason even if there are no other objects). Of course, it runs out of RAM occasionally (Vista hogs it).
Reply in the comments if you want.