Years ago there was a thread asking what games launched with the Sega Genesis. Most of the true launch games were listed, a few were not, and some people insisted some games like Golden Axe, Revenge of Shinobi, Pat Riley Basketball, Herzog Zwei, Phantasy Star II, After Burner and Ghostbusters were at launch, when they were in fact not.
Genesis had two launches in the U.S. - A test market launch in New York City and L.A, on or around August 14th, 1989 and a nationwide launch in mid September 1989.
I can't really speak about what was out for the test launch since I didn't see it, I've only read about it online years after the fact.
I can tell you what games were out in September for the nationwide launch, going by memory of the actual roll out that I remember. I lived in the Chicago suburbs at the time. Toys R US and Babbage's in Niles, IL. is where I bought systems & games.
These are the Genesis titles that were available day one, at the places I bought games and for the most part, nationwide, on or around September 15th 1989:
actually out at launch
*Altered Beast (packed in with the Genesis for $189)
*Space Harrier II
*Super Thunder Blade
*Last Battle
*Tommy Lasorda Baseball
*Thunder Force II
within days or weeks of launch / upto a month after launch
*Ghouls 'n Ghosts (Oct 1989 ?)
*Arnold Palmer's Tournament Golf (Oct 1989 ?)
*World Championship Soccer (Sept - Oct 1989)
*Super Hang-On (Oct 1989)
over 1 month after / several months after / well after launch
*Forgotten Worlds (Nov 1989)
*Rambo III (Nov-Dec 1989)
*Zoom! (late 1989 or very early 1990)
*Golden Axe (December 1989, ~3 months or so after nationwide Genesis launch. Golden Axe was most definitely NOT a launch game, nor was it out within a few weeks of launch, or even a month after. I pretty much do remember seeing it at TRU in December, before the new year. IIRC it was LATE in December. Golden Axe was the most significant Genesis game actually released in 1989, since after launch. If the english version of Phantasy Star II for Genesis had actually made it out in 1989 (it did not) then that would've been the most important game for Genesis of 1989, but Golden Axe took that position.
*Revenge of Shinobi (December 1989 ~ January 1990) I don't remember for sure the actual month it was released. I'm pretty sure it was Dec or Jan. I know wasn't a launch title though. It wasn't out in Oct. and probably not Nov. either. According to Gamefaqs the Japanese version, Super Shinobi, wasn't out until early Dec 1989 and it obviously came out at least shortly before the retitled Genesis version.
*Alex Kidd in the Enchanted Castle (sometime in late '89 or early '90)
*Mystic Defender (late 1989 or early 1990)
*Truxton (late 1989 or early 1990)
*Phantasy Star II (March or April 1990, 6-7 months after launch)
The big one! Phantasy Star II was not out until sometime early 1990...Even though copyright 1989 is on the title screen, box and manual. The Japanese Mega Drive version of PSII came out about a year earlier, in March 1989, which was before Genesis launched here, and before most gamers including myself even knew the Genesis existed! I got my Genesis in April 1990. I bought PSII soon after that, also April 1990. My reciept for PSII says 4/17/90.
I know I did not see PSII in TRU or Babbages until after I got my Genesis. For me that puts it at mid April 1990. That's the best I can do. during those months I visited TRU and Babbages usually once a week, and not more than 2 weeks would go by at most between visits. It is possible PSII came out a little bit earlier than mid April 1990, but not by much. Maybe other parts of the country got it earlier, but that was still early 1990. Just for fun I did a narrowed-down usenet search on google groups. People were talking about PSII as if it had been released , and as if they had it, in March 1990, and not before that. Amazingly, Phantasy Star III came out in Japan in April 1990, about the same time that we got PSII !! (if only a month later) We would not get Phantasy Star III in the U.S. until about the middle of summer 1991.
*Herzog Zwei
(about the same time as Phantasy Star II, maybe shortly before. I first saw Herzog Zwei in April 1990)
*Air Diver (probably March-April 1990 but as early as Jan-Feb)
*Super Hydlide (about the same as Air Diver)
( I noticed Herzog Zwei, Air Diver, Super Hydlide on April 17 at TRU. IIRC, I had not been there for a few weeks. The TRU flaps/cards for the game boxes of these 3 were all lined up together. This was the same day I bought Phantasy Star II)
Pat Riley Basketball (early or mid 1990)
Ghostbusters (summer 1990)
Michael Jackson's Moonwalker (August 1990)
After Burner II (August ~ September 1990, about a year after launch)
Super Monaco GP (around the same time as AfterBurner II)
Buster Douglas Knockout Boxing (late summer, early fall 1990. This was one of the first games used in Sega's "Genesis Does" campaign)
Sword of Vermilion (fall 1990)
Thunder Force III (fall 1990)
Strider (November 1990, more than a year after launch)
any corrections, additions are welcome.