Radiant Silvergun requires less math than Ikaruga to enjoy, so it might work out a bit better for you!
alright, I guess I should put in my next recommendation installment.
Now I’ll go with horizontally-scrolling shooters for Saturn (ignoring whether it was originally an arcade game, by this point most of them are).
Metal Black - has one of the coolest “in-engine” intro->gameplay sequences I’ve seen:
Hyper Duel - it’s pricey, but very fun - it’s short, your “ship” turns into a mech whenever you like, and the “original” vs “arcade” modes are so different they might as well be total remixes, which means it’s actually worth playing through multiple times.
Thunder Force V - well, it has the song Legendary Wings in it, which is enough reason to play the game, but also it showcases that old style of 3D where they’d make impossibly skinny structures attached to bulky engines and bodies and stuff, which rules. This version is also best to play because some stage detail is missing from the PS version
Darius Gaiden - quite a saturn graphical showcase. even if it was originally in arcades, it feels like it was made for the saturn. Proper transparency, huge scaling sprites, faked perspective, it’s all here! And that music, too!
I’ll be back in a while with another specific group of games :3