How to get points faster for the shop
To enable the shop, you first need to finish the game in normal mode at least 1x once; all your ingame achievements will be turned into points/score for the shop as soon as you get them. However, the Shop will only be available when you finish the game first. The following steps are still advisable to follow, even if it’s your 1st playthrough.
The 1st way of getting those points is to play through the main game normally as MANY times as you can without getting bored until you get all of those achievements.
There is a 2nd way however: for specific in-game achievements that are harder to get, you can just save & load, like the “get 3 fuses under 5mins in the warehouse” for example.
A lot of the high score achievements are related to Kill Numbers of zombies you get in the game, note that you can also save & load anywhere in the game to achieve this.
Having both the Assault Coins and Samurai Edge in your inventory will help killing zombies faster for this. But it isn’t mandatory.
There are many good places in the game just for killing zombies and then loading and killing them all over again; For pistol gun, you can pretty much do this anywhere in the game. But I recommend you wait until you get to Carlos Chapter, by the end of his Ark there’ll be a Hospital Zombie Raid, once you get there you’ll need save the game in a secondary save slot of your choice, then once you finish the raid, save the game in the main slot you’re used to save, then load the secondary save-game slot whenever you feel like killing as many zombies as possible to get the achievements. Keep doing this until you get all the kill counts you need for each of the Gun Achievements.
The game doesn’t care if you’re saving & loading, it only looks at the kill count variable. 🙂
The same goes around for pretty much every other single achievement in this game’s existance.
The Hospital Zombie Raid is the best place to get all of the gun achievements, IMHO. So make sure you save enough bullets, shells & granades for doing this without a sweat. Also make sure you don’t overwrite the save-slot of choice for doing this OR you’ll have to play through the whole game again just to get there.
For some of the other achieves, you’ll just really need to play through the game.