Touhouvania (2 especially, major improvement over the first) is probably my favorite castlevania-alike game. Awesome soundtrack, great art, unique blend of bullet hell and CV elements, it's a tragedy that there's no news for a 3rd game.
For fans of the metroidvanias, La Mulana is another great game that I'm sure has been mentioned before. Much harder than the metroidvanias as you can't grind your way to victory; all upgrades are found in a way similar to metroid. The healing system is also quite restrictive. The area designs and music are great, some places have like 32 layers or something absurd like that.
Bunny Must Die is a really great game with a boss that's suspiciously similar to a certain CV character
http://youtu.be/WgEAzw0_hB4Game is pretty difficult, but has a lot of potential for cool stuff thanks to the really neat parry system inspired by street fighter. You can glide across lava and spikes if you're skilled enough. Also, if you thought the 2nd castle of SOTN was cool, just wait until you see what you unlock at the end of this game.
Lastly, rosenkreuzstilette is game that combines many elements of classic games, primarily megaman but also ghosts n goblins and CV. The area designs in particular are very reminiscent of CV, and while they're fairly simple they're still gorgeous.
http://www.spriters-resource.com/pc_computer/rks/sheet/28057/