APK MOD INFO
Name of Game: The Blockheads
VERSION: 1.6.1.2

Name of the cheat, mod, or hack (credits: wendgames):
-UNLIMITED CRYSTALS/UNLOCKED

The Blockheads MOD APK 1.6.1.2 (Unlimited Crystals/Unlocked)

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