APK MOD INFO
Name of Game: Stupid Zombies
VERSION: 2.0.3

Name of the cheat, mod, or hack (credits: wendgames):
-UNLIMITED AIR STRIKES

Stupid Zombies MOD APK 2.0.3 (Unlimited Air Strikes)

Download the CACHE file/OBB file. They should be .zip or .rar files.
Extract the file to your sdcard.
Move the extracted folder to the location: /sdcard/Android/obb