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The following Gmod addons were used;
Map: http://www.garrysmod.org/downloads/?a=view&id=95561
http://www.garrysmod.org/downloads/?a=view&id=101035
http://www.garrysmod.org/downloads/?a=view&id=53742
http://www.garrysmod.org/downloads/?a=view&id=100857
http://www.garrysmod.org/downloads/?a=view&id=131869
http://www.garrysmod.org/downloads/?a=view&id=109315
The song is, obviously, Zombies on your Lawn, the ending credits song to Plants vs Zombies.
▶️ DTube
▶️ IPFS