I guess I'd personally rather put Dragon Breed or Cosmic Cop up there, but they didn't get as much support.
Dragon Breed is an interesting choice I'd overlooked, though some might argue that its run-n-gun elements would disqualify it...Gallop, on the other hand, I would consider a bit too specialized in its innate appeal (i.e. hardcore memorizers only) to really fit here as well as the rest.
X-Multiply has a much different feel than R-Type, but I can see having trouble making it really stand out on the write up.
Seems there's more than one person out there eager for me to reconsider my position on this...will dig further.
Magical Chase's influence - Air Rade, Gundemonium, Deathsmiles, Trouble Witches. Each has sequels, too. Also it being in a very similar vein to Coryoon, Air Zonk, etc., makes it feel less special to me.
I can see the similarities in the others, though TW still sticks out to me as the most direct offshoot, especially with the shop. In any case, the TG-16 isn't my greatest area of expertise personally, so I'm going to be pretty reliant on the community to help me pick out the most interesting stuff for that system in particular: if there's enough consensus for or against a particular game, I won't be in much of a position to resist it, heh.
Needs more NMK
I was tempted to put Gunnail on there, but doesn't that one have the wacko Under Defeat-esque scoring system that gives more points as you lose more lives? Thunder Dragon 2 I was willing to grant a spot in Tier 3, but everything I've experienced regarding Rapid Hero says to me "not bad, but also incredibly generic". Am I missing something about it, or could I just as easily give the spot to, say, Shienryu?
Omega Fighter Special ought to at the very least get a mention.
I think that one's pretty well set.
Hellsinker fans, I hear your pleas, but methinks that one will have to wait for the doujin equivalent article (unless one of you pens a Hellsinker-only missive of your own volition, of course!).