the good ol' days
100% with you on Sega-CD as a great system too, the more i explore it the more i appreciate it too. sucks that i sat on its library for so many years, certain i could still pick up CIB robo aleste, heart of the alien, road avenger etc on the cheap one day (since as you said, it was for so very many years)
Robo Aleste is one that I don't have in my Sega CD collection, but I kind of want it. Off the top of my head, some of my favories are:
Silpheed - Yeah it has FMV backgrounds, but it still plays like a vertical shooter.
Final Fight CD - This one oddly came in a cardboard case, which I lost, but it is the best 16-bit home console port of the original Final Fight.
Earthworm Jim: Special Edition - Favorite version of the original EWJ
Mickey Mania - This one is also on the Genesis and SNES, but the Sega CD version is my prefered version.
Road Rash - Oddly the best of the 16 bit Road Rash games, but really hard to find. I used to rent this a lot on the Sega CD, but I could never find it to buy.
Sonic the Hedgehog CD - This one has been remade by Christian Whitehead in HD, and to be honest I kind of prefer his port over the original. But I have always been a big fan of Sonic CD.
The Terminator - It's a huge improvement over the Genesis game. Not the greatest run and gun platformer ever, but it is still solid.
Eternal Champions - cheesy fun, but i like this one more than the Genesis version.
Panic - Quirky Japanese point and click type adventure. It has a lot of humor in .
Soulstar - One of the most impressive uses of the Sega CD scaling hardware on the console. Some of the levels do drag on a littlem but it is a decent 3D sprite scaling shooter. Developed by Core who made quite a few games that pushed the Sega CD scaling hardware, like Thunderhawk, Jaguar XJ220, BC Racers and Battlecorps.
Ecco the Dolphin and Tides of Time - Both are pretty well straight ports of the Genesis game, but if you lie this series, the Sega CD versions are worth getting for their soundtracks.
Android Assault - Not bad at all, much better than the terrible Sol Feace.
Lords of Thunder - Inferiour to the Turbo Duo version, but I still don't think that this is a bad shooter on the Sega CD by any means.
Batman Returns - Hard as nails driving sections that are kind of neat, but the platforming sections were ported from the Genesis game.
Plus there are the also rarer titles like Popful Mail, Lunar and Lunar Eternal Blue, Shining Force CD (really wonder game if you can find it), Keio Flying Squadron (this game is worth a fortune, for some reason) and of course Robo Aleste which I previously mentioned.
yeah Gunstar Heroes, Bloodlines, Mega Turrican & a few others jumped but not too many surprisingly
The Sega Genesis version of MUSHA still goes for a lot of money, and Crusader of Centy fetches for some outrageous prices too (probably thanks to the Atlus name on the box). I have never owned Crusader of Centy but I remeber renting it more than a couple times when I was young. It's decent, but I wouldn't pay the prices it is going for. The Japanese Mega Drive game Panorama Cotton still goes for a lot too.
But on a whole, Genesis games haven't hit SNES cart prices yet.