To get this achievement you must unlock a crib (can be done in first crib), once you are in your crib go to the T.V. and hit Y. This will bring you onto a screen asing you what you want to do, just press RT and and click A on zombie uprising.
This game is easy if you play it properly, but if not it can be a pain. To start off with turn around and run along the side of the building as there will be food and ammo you will need to help you along the way. Once you have gatherd everything avoid the zombies and walk across the square. You should see a set of stairs, walk up them still avoiding the zombies. once your at the top go to your right and walk along the balcony, on the floor there should be a minigun save this for later.
Now just use the melle attacks on all the normal zombies until you get to wave two, on this wave there will be tall zombies and fast zombies. The tall zombies are stronger than any other zombie so don't expect them to go down in one hit, as far as the fast zombies go there the same as normal zombies.
Now once you get to wave three you will have to watch out for the flame zombie's as these will burn you and this will take alot of damge. just head shot these and stay away from them. now that you have the basics down just rinse and repeat and should get the achievemen't.