Great job! The art and sounds were spot on. It was really liking take a trip back to the SEGA goldenage. A few suggestions would be to make the music loop, it would run out if I couldn't find the key and exit in time. Every once in a while, when I killed an enemy, he would stay on the screen but I couldn't do anything with him - hit him, he wouldn't shoot me, and etcetera. All-in-all this was done excellently. I was especially fond of the background, tilesets, and bubbles!