Russki Duck
There's a duck who lives a life of danger
There aren't many Apple II games quite like Russki Duck--the Cold War tactical espionage action game where you are a happy face and enemy spies are jack 'o lanterns. If anyone remembers the "MX Program," it plays a role here; top-secret plans labeled with an "MX" are hidden somewhere in a vast one-screen metropolis, inside a rubber duckie, 'cause who would ever suspect that?
Word must have gotten leaked out, however. The neighborhood is swarming with enemy spies (eight to be precise). Their behavior consists of randomly walking around the overworld map, going inside buildings every so often, stealing something, walking back out, going into another building, putting the thing in there and then stealing something else, at which point the act becomes a cycle. Aside from killing you, that's all the purpose they have.
You actually get to walk around this overworld, as a white dot. Bumping into the red dots on the street does nothing but stop your pace. Within the stores, however, you'll become the happy face and they'll recognize you (unless they're busy carrying something). The map follows Pac-Man physics, so if you don't want to brave crossing the street, just go to the left and come out on the right.
The controls are odd but you'll get used to them: A and Z move you up and down, while the left and right arrow keys maneuver you left and right. If it bugs you that much, Control-C lets you redefine the controls. S is also handy as it lets you use an item, though there are only two items you can really "use."
One of these is the hammer, so you should get it right away while it's still in the building it's supposed to be in. You start out in the CIA building. Remember where it is because this is where you'll be returning the stolen plans (more specifically, inside the laser-protected room).
Go outside and enter the building below the one you were just in. The hammer should be there. Now you can mash crates with the S key whenever you find them (they're blue or orange boxes with a big X on them). 99% of the time, these boxes will contain a bomb, meaning you should exit the room right away. But ONE shall contain the Russki Duck. (You should also keep in mind activating a bomb in any room blows all the items in that room into another random building. Also: there was this one time some idiot jack 'o lantern stole an active bomb and followed me into the other room with it. But it only happened once.)
Once you have the duck you can just break it open with the hammer, right? Think again. You need a key to open that. The Key Duplicator store is the fourth building on the right side, but don't count on the key still being there, due to the random sticky fingers of the pumpkin heads. Once you find it and use it, the duck will turn into a square with "MX" on it. No, it's not over yet.
Now you must find the CIA password card, which you would think you'd have yourself, being a super secret agent and all. But you don't and you must track that down to deactivate the laser in the aforementioned laser room, so you can stick the plans in there. Once you've done that, you'll be awarded $2500--but the game won't end; it never does. Just know this is your ultimate goal.
What makes Russki Duck fun is walking around the city on a Duck Search, and there's a way to get the duck right away, but I'm not telling you how. If you really want to spoil yourself you can go to GameFAQS for that, but do so at your own risk.