The Mean Streets (map name: sr3)

Do the little platform jump thing down the busted spiral staircase and pay attention as you'll need to come back up later. Then go through the only unlocked door and down the alley. Go inside the only building you can, and enter the door to the left (the one on the right is locked). Head up the stairs on the left to the top of this building.Take two rights and open the door to find a thug waiting, along with jacket armor, two medkits, and a couple of boxes of shells - you'll need them all soon!

Leave and head back downstairs; outside the small room take a left through a door into another room. Climb up the stairs and jump out the window (the one on the right) and walk carefully down the ledge to the window across the alley. Kill the guys there and go inside to get a couple of medkits, three boxes of shells and some flame-thrower gas for later. Activate the switch on the wall (which unlocks the first door on the right you passed coming into this building). Then jump back out the window, and fall down to the boxes below on the street. Go back into the "cathedral building" and into the door you unlocked (first right). Walk down the hall to the next door with the exposed wires in the ceiling and get ready to deal with another mean dog. Once he's been put down, smash the boards on the window and jump down to the street below.

Walk down the street to the door, fraggin another dog if you must. Then use your crowbar to bust open the floorboard of the broken down car to find the ammo hidden inside. Follow the street to the next door, go inside, and walk downstairs. Continue down the hall, up a set of stairs, and watch for enemies as you go. Continue, keeping left, up the stairs, and through the next door. Take a left down the street, get your favorite weapon out, and enter the first door you see on the right. Kill them all, and take their dough (armor and shells on the table at the back of the room). Exit by the door in the rear left of the room. This will take you (only briefly) to the next level.

The Jesus (map name: sr4)

Continue down the hall until you find an open junkyard. Kill all the nasty mutts in the yard. The battery you need is hidden in the trunk of a car in the tower of junk cars on the right. Climb up the side of the stack of cars that forms a staircase and get the battery.

BTW - There is a load of health in the service pit in the garage (activate the switch to raise the car to be able to climb up the ladder and out of the pit). Even better, just use the pit as a sniping position to clear out the thugs in the area (including the dogs if you make them follow you into the garage). Before you activate the switch to raise the car, climb up the ladder underneath it as far as you can and pick off your victims as they run around the garage, unable to attack you! Take yer battery and head on back the way you came through "Mean Streets" (map sr3) to "The Super" (map sr2). You'll meet lots of new pissed off thugs and bitches on your way, so don't get too comfortable.

The battery will let you start (and ride!) the motorcycle near the bar (Jax). Touching the motorcycle will install the battery automatically...

...and then you get to ride off into the sunset and dig the next cut scene!