Remember Sparkster AKA Rocket Knight Adventures?
http://www.youtube.com/watch?v=Ix2Vuvo_-ZQ

Here comes Rocket Knight again, and it's a killer!
http://www.youtube.com/watch?v=JheuaSpca5Y

It's got all: nice 2.5D cell-shading graphics, cool knight with a huge sword a jet-pack and casting fire-balls character, silly story, challenging weapon&fighting system, flying shmup-alike levels, normal "walk, gather stuff and kill" levels and huge bosses which require some tactic to get rid of. Just like in the good old days.
Try it out, it rulez!