It's all good, at the very least you now know about it.
You can now get all of the Gradius games on the Gradius Collection for the PSP, but for Gradius V you'll have to get it for the PS2.
As for R-Type, just get Final R-Type to get the chance to play with practically every single ship that appeared in the series, and some fun ones. I was sure though you've played Final R-type as well...