I emailed Keith Robinson about the M network games, and while he didn't have specific months he did tell me the order their games came out in and what year - Adventures of Tron is an 83 release (the first one, if I recall).
Can you post that list?
I haven't been able to track down a specific month for the Supercharger games, but based on the ads in magazines I chalked it down to July/August myself.
If you can believe Arcade Express, July is too early:
The Supercharger for the Atari VCS went on sale in 40 Broadway Department Stores in Southern California at the end of August, and the company describes early consumer reaction as "exceptional". The $70 Supercharger, which increases graphic resolution capabilities of the VCS, comes with one game, "Phaser Patrol". Three additional games, "Communist Mutants From Space", "Fireball", and "Suicide Mission" will be marketed this fall for $15 each.
"Consumers came in, took a look, then came back and bought, reports Ken Hall, a spokesman for Arcadia. The Supercharger next goes on sale in Northern California, then Chicago, New York City, and Detroit. It should be in 10 major markets before Christmas.
Meanwhile the company is still seeking a new name, since Arcadia was previously tagged by Emerson for the Arcadia 2001 videogame system. The new moniker should be chosen soon.
August is also the magic month according to Video Games magazine:
Announced in April, the company plans to have four games and its Supercharger unit ready by August. What's unusual about all of this is that the games are recorded on cassette tapes ($14.95 each) and must be played back by first plugging the Supercharger ($69.95) into the VCS, then connecting it to a portable tape player. Not only are the cassettes cheaper, but the graphic resolution is of extremely high quality. Fireball, Suicide Mission, Communist Mutants from Space, Excalibur (not the film), and Phaser Patrol are Arcadia's initial game titles. The last game comes complete with the Supercharger.
Hmm... I wonder if the game with the lowest copyright right date instead of release date should count as the first since there is a difference between first coming to market and first coming into existence? Especially since release dates would be more lost to history than copyrights.
A copyright date can be way off from when the common man or kid could get the game in his grubby little hands, so I'd rather stick to the actual month a game was released in the USA.
Besides scouring every magazine available online, we can try to find some Atari lover who worked at a department store who kept paperwork (or made copies or wrote things down in a notebook) showing when games arrived at the store. There has to be at least one Asperger-ish or high functioning autistic guy who worked at a department store that kept a record of the first time a new Atari 2600 game came in.