This!
http://www.the-underdogs.org/game.php?name=G-Type
It's a nicely done fan designed game with elements from both Gradius and R-Type. For instance, although the power up system is straight out of Gradius, the weapons themselves are borrowed from R-Type. Let me tell you, the R9 force unit really comes in handy when the screen's flooded with bullets... you'll wish you would have had it in Konami's official Gradius games!
You really should give this a spin if you liked either R-Type or Gradius. It's not quite as good as the games that inspired it, but it's a nice shooter in its own right. The audiovisuals are comparable to a high quality Super NES release and some of the boss fights are pretty imaginative. Furthermore, there are a lot of rounds, although you'll have to play the game on every difficulty setting to see them all.
JR
P.S. I was able to unlock a boss attack mode called "The Hole of Inferno"... I'm not sure how, but I think you've got to beat the easy and normal modes, then choose sixteen lives and the hard difficulty setting in the options screen.