This game is fantastic, and the difficulty level is right up my alley.
Regarding the difficulty level, since others seem to be complaining, the levels do ramp in difficulty properly. The first level IS NOT the hardest level, the last one is (requires exceptionally precise timing).
Games with difficult levels like this don't play like normal platformers - you must be patient, and plan your moves much in advance of doing them. All of the levels have 'safe zones', where nothing can hit you; all you need to do is plan your movement to these 'safe zones' (the first level has plenty, the last level only 3).
The only true flaws this game has regard the orbiting spike blocks: they are supposed to bounce off of you but sometimes (the fast moving ones on the last level) can get stuck inside you. Not a huge problem, since the easy solution is don't get hit. haha. A second possible flaw (unless it was intentional) was the moving platforms don't carry you with them and move slower than your walk, so you have to rapidly tap the arrow keys to position yourself on top.
I spent about 2 hours playing this awesome game, and I can play through the whole thing with <5 lives. (I can get all the way past the first boss without even losing a single health). If you want, message me and I will create a video walkthrough.
I would, however, put somewhere in the description that all of the enemies need to be killed to unlock the finish door. You might also consider putting a warning in future games of this difficulty, since the general NG audience may not be apt to these kinds of games. Make it like the entrance to porno sites (you didn't click 'exit', you knew what you were getting into).
Overall, very solid mechanics, great gameplay, I loved it! ^^ In games like this, the mechanics of the platformer engine itself REALLY matters (a properly difficult game shouldn't have the controls fucking you too), and this game play beautifully. Haha looks pretty too.
Great work, especially if you are new to this. Going to play the first Ghost Light.