Editions are special versions of the Chicken Invaders episodes that are based around certain holidays. They come with the original version if you buy one on InterAction studios website, or as DLC on Steam. The only games that don't have any editions made for them are Chicken Invaders and Universe.
Editions usually replace graphics, sounds and music of the game with elements related to the things they cover.
These editions usually have the most effort going into them, with most of the graphics, sound and music being replaced with Christmas carols (e.g. Jingle Bells, Joy of the World, Deck the Halls, etc). For example, only the Henterprise theme remained intact in Cluck of the Dark Side's Christmas edition.
Most InterAction studios games, including Piggly, Island Wars 2, and Loco also receive those editions.
Christmas editions are being made since The Next Wave.
Easter[]
These editions usually have the least effort put into them compared to other editions. Only the graphics and sounds get replaced.
In Ultimate Omelette, the in-game text does get changed, though for only most of the waves that contain the word "Chicken" being replaced with "Bunny".
Thanksgiving[]
In these editions, the graphics and the main theme music is replaced. They are unique from other ones in that the cutscene and in-game text is changed appropriately, since Chickens get replaced with turkeys. It was also why this edition started out with English being the only language available.
Thanksgiving editions are being made since Ultimate Omelette, and so far it's the only game that has a Thanksgiving edition.
Halloween[]
Those only have the graphics, sounds and the main theme replaced.
Originally, the editions were only available when the holiday they celebrate arrived. Due to popular request, however, InterAction studios decided to make them available since 2004.
Revenge of the Yolk Christmas Edition is renamed Holiday Edition in some countries.
Ultimate Omelette is currently the only game with the most Editions.
Cluck of the Dark Side does not have a Thanksgiving and an Easter edition yet, but they might be made after Universe is out.
In Halloween and Christmas editions of Cluck of the Dark Side, most of the Hero's dialogue were removed, notably in boss waves.
Ion Blaster Gift • Neutron Gun Gift • Laser Cannon Gift • Vulcan Chaingun Gift • Lightning Fryer Gift • Plasma Rifle Gift • Utensil Poker Gift • Atomic Powerup
Ion Blaster Gift • Neutron Gun Gift • Laser Cannon Gift • Vulcan Chaingun Gift • Lightning Fryer Gift • Plasma Rifle Gift • Utensil Poker Gift • Boron Railgun Gift • Photon Swarm Gift • Positron Stream Gift • Atomic Powerup
Ion Blaster Gift • Neutron Gun Gift • Laser Cannon Gift • Vulcan Chaingun Gift • Lightning Fryer Gift • Plasma Rifle Gift • Utensil Poker Gift • Boron Railgun Gift • Photon Swarm Gift • Positron Stream Gift • Hypergun Gift • Riddler Gift • Corn Shotgun Gift • Atomic Powerup