First of all, you need to learn this route (maintenance tunnel) it will take you around 10 laps to fully master it.

Also, i highly recommend beating the game at least once for general location knowledge.

*Attention*

Some people reported that their game crashed while having a few thousands of zombie kills, so its preferable to save every now and then, the easiest way is to grab the key that is located in the maintenance room (located in the middle of this area, in the tip of the pen1s looking road).
Grab it, open the map and look for the nearest save spot, be careful tho, theres a lot of zombies inside that room, thats why its recommended to grab the drinks that i will explain later in the guide.

1.- Start a new 72 hour mode game


2.- Skip the helicopter intro.


3.- When you make it to the safe room, dont go to Brad, let him fight Carlito (no matter how much time passes, the case will never be over).


*Optional* Get the Horror novel 1 and 2 magazines in The Sinister Read at Entrance Plaza and Bachman Bookporium at Paradise Plaza in case you want some extra points and need to level up.


4.- Pick up some wine or orange juice in case your car gets wrecked and you have to walk to the next car (which will most likely happen).
*** If you decide to go for the wine and the magazine, your only way to go there is from the court food, the carlito fight will trigger but dont worry, just grab the wine and go all the way back for the magazine and leave, the scoop will start draining but it will never fail***


5.- Now go to the Leisure park parking lot and get in the red car.


6.- Go inside and follow the route. Try avoiding the zombies with the big propane tanks, its not possible to avoid them all but try to as many as you can to avoid wrecking your car mid run.


7.- Instead of turning right first, i killed the zombies in the parking lot on the left.


8.- Repeat this over and over again until you are done. (Took me around 4 hours of non stop driving, each lap nets you around 1000 kills, that means youll be doing around 60 laps).


(I saved when i had like 28k kills just in case, and on my way back i killed the convicts with a bat, which is pretty easy once you know how to kill them and then took their jeep, which lasts around 2 laps or if you dont want to waste your time doing this, just go to the room i mentioned at the beginning of the guide and save there)


9.- Once you are done, (DONT QUIT, BEAT THE GAME AND GET THE ACHIEVEMENT OR YOU WONT GET THE REAL MEGA BUSTER) go back to the helipad (upstairs in the safe room) and wait till the chopper comes to pick you up (day 22, 12pm in-game time) or save some survivors for massive xp, or keep killing zombies.


10.- Save and youll get the real mega buster unlock prompt.


11.- Start any mode, and the mega buster will be waiting for you next to the other unlocked costumes in the safe room.

And thats it, following this guide will help you get, a *maybe* level 50 Frank West, the real mega buster which makes everything easier and the zombie genocider achievement. Any questions dont hesitate to post them in the comment section.