Very hard, but I like it. Seems very possible to use less powerups. Personally I only take the armor up, because it's a dangerous world. Still it was very hard, I only made it until the vacant area with red bullets flying around in it. Was I near the end?
I also like the audio/music especially the game over one. Makes it less annoying to start over. Graphics are bright and nice to look at. Movement was smooth, uses conventional controls,. So overall, great job!