Halo 2600 ????

What is Halo 2600?

It’s a homebrew Halo game for the Atari 2600 made by Ed Fries, former Vice President of game publishing at Microsoft and one of the people behind the original Xbox (as well as one of the people responsible for Microsoft buying Bungie). He explained his reasons for making the game here.

Halo 2600 is not an official Halo game released for the Atari 2600 in 2010.

Best to use this for more info friend as it gives an alright overview on it.