1943 kai is ridiculously impressive, but not well known.
Also, half serious about bravo man.
You're thinking of 1941 Counter Attack. But both are well known.
Sorry I really do mean 1943. Tons of enemies and parallax, with lots of bullets all at once, with no slowdown except for 2 seconds for literally one time. Also some gigantic bosses, though there is flicker.
And this was all with 4 Megs.
And I will also add Darius plus. That conversion floored me, and they still added extra bosses.
But 1941 was proof that the Supergrafx needed to live longer though.
1943 Kai does toss around more than SNES games, but by PCE standards it's just an acceptible port of a repetive game. The new content is cool, but Soldier Blade, Final Soldier, Super Star Soldier, Dragon Saber, Tatsujin, Hana Taka Daka, R-Type, Aeroblasters, Magical Chase, Download, Air Zonk, Coryoon, Detana Twinbee, Dead Moon, etc are all 4 meg HuCards. BlaZing LaZers, Sinistron and Chuka Taisen are only 3 megs. But the pixel for pixel arcade-superior port of Sidearms, the much more impressive and variety filled arcade game running on the same hardware as 1943, is only 2(!) megs.
The PCE just happens to specialize in content-packed small sized HuCard shooters that toss around insane amounts of sprites and feature killer music. 1943 would be special on SNES, but it's nothing special as far as HuCards and MD cart games go.
Darius Plus is indeed impressive, but it did not add anything new. Super Darius on CD2 has the extra bosses.