Now, if you owned a Genesis, and were into shmups, you probably owned at least one that was developed by Toaplan, perhaps most notorious as the creators of Zero Wing. Translation snafus aside, the games they made tended to be competent, if not spectacular, and generally had the feature of having the first stage music be the best in the whole game. A couple of examples of this principle in action:
Hellfire Stage 1 (Arcade)
Zero Wing Stage 1 (Sega Genesis)
Speaking of shmups, while Thunder Force IV is known one of the few games that took the fullest advantage of the Sega Genesis's sound hardware, Thunder Force 3 was no slouch on the matter either.
While Konami is well-known for producing excellent soundtracks from anyone at any time (the soundtrack for the original Castlevania was done by a girl fresh out of college as her first job), there are still a couple that fell through the cracks due to not being available in the US. The actual Metal Gear 2 (not Solid 2) wasn't released in the US until Metal Gear Solid 3: Subsistence edition came out, and the game does have a superior soundtrack on top of being a superior game.
More to come as I think of it.