this is a text tutorial.

when you start shoot a zombie 6 rimes and knife it (round 1)
on round 2 shoot it 8 times then knife it
on round 3 stay on the upstairs and knife the zombies 3 times

open the door upstairs then run to the right
on your right hand side should be a gate looking door costing 1250
open it and go to the right then run up the stairs, then up the stairs again
open the door and turn on the power
go box ONCE
i had a spas-12 when doing this.

open the door that is behind the power
open the door for the lunar lander then call it and take it back to where you started

now go upstairs and go out of the first door you opened
go left and open the gate now when you get to the end there is a door on the right
open it and call the lunar
ride that back to where you started

run upstairs again
go right then go round a truck then run left

go upstairs and call the lunar
take it back to the middle and run upstairs
go to the power and press x on it
run to the closed pack a punch door
go right and PACK A PUNCH