Chicken Invaders: Ultimate Omelette (known also as Chicken Invaders 4) is the fourth main installment in the Chicken Invaders series, released on 29 November 2010 as a demo, with the full version releasing a week later. It is the first game in the series to be released on Valve’s Steam platform, and the first to receive an accolade, as it was included in the Adrenaline Vault’s Top Casual PC games of 2010. Ultimate Omelette had a Christmas Edition released on 24 November 2011, an Easter Edition released on 11 March 2012, and a Thanksgiving Edition (the only Edition in the series to be themed around the Thanksgiving holiday), which was released on 15 November 2013.
[Source: wikipedia.org]