Name of Cheat/Mod/Hack (credits: wendgames):
Alien Defense MOD APK 1.7 (Mod Money)
1. Install MOD
2. Play or continue to install cache (obb) file if available to download
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