MUSHA...one of the best SHMUPS ever.
Eh, it is good (Compile made great shmups!), but of Compile's shmups, I like Robo Aleste, Space Megaforce, Blazing Lazers, and maybe some others more than MUSHA. Plus it's also quite expensive now.
As for the Sega CD shmups, Robo Aleste, Silpheed, and Keio Flying Squadron are exceptional, right up there with the top Genesis shmups in quality. Android Assault is pretty good too, but feels too uninspired and derivitive, for me. It's basically Thunder Force crossed with Gate of Thunder, but not done as well as TF IV or Gate of Thunder. Still, it's an okay game. Sol-Feace is also okay. It's fairly average in design, but it's a solid, quality shmup well worth playing if you like the genre. And last, Lords of Thunder isn't quite as good as the Turbo CD original version, but still is a pretty good game.
As for import titles, there weren't any Japan-only shmups; we got them all. Devastator does have some shmup-style parts, though. That is a fun game I definitely like. It is too short, and can be frustrating, but otherwise, decently fun game. I wish that Devastator, Night Striker, and The Ninja Warriors had been released here.
And finally the 32X... Zaxxon's Motherbase 2000 is a decent Viewpoint-style game. It's not as good as Viewpoint for the Genesis, but the graphics are better, and it's definitely worth picking up if you have a 32X. Do expect Viewpoint and not Zaxxon (it's not really a Zaxxon game, in Japan the game was just called "Motherbase"), but the enemy-takeover mechanic (a bit like BlaZeon for SNES, and I love that game) is cool, and the game plays solidly well. Kolibri is good too, though that's mostly open-movement, not autoscrolling. It is the best hummingbird-based shooter, though... but expect a challenge! It's from the people behind Ecco.
One of the worst SHUMPS ever. hahaha
My friend and I used to call it Sol-Feces after its Sega CD Sol-Feace labeling.
Sol-Feace is a good game. It's somewhat average, but on the good side of average. Fun little game, particularly for Sega CD.
If you want some actual subpar shmups for the Genesis, some (again US-released titles) I don't like so much include Arrow Flash (it's so boring!), Forgotten Worlds (it's average, nothing more, plus if you're using controller extension cables it requires 3-button controllers to run), Battle Squadron (subpar Euroshmup), Task Force Harrier EX (bland and tedious), and Twin Cobra (it's not one of Toaplan's better games, and the port is overly difficult and frustrating. You can't see far enough ahead! Play any other version of the game over this one.).