Maybe this is the most spectacular and known Easter Egg. This one works on the later versions of the game, and in co-op. too.
● Minimap with important marks:
Minimap with important marks
● Do the objectives, except the last one: "Gather in the extraction zone". Kill all enemies, more or less
there are 44 of them. Find the four dead allies, get their dogtags.
Dead allies
Dead ally
Dead ally
● Then find and shoot the three skulls on the
map.
Minimap with important marks
First skull
Second skull
Third skull
● After this go to the extraction zone (Not with all of your man, don't complete the mission.) and wait.
● Three man will came from the end of the map. Follow them back to the houses, and enjoy the
show.