I hadn't played Fusion or Zero Mission since they respectfully came out. So I decided to play them again. I beat Fusion yesterday and popped in Zero Mission. Now, I like Zero Mission, but I prefer the art of Fusion. It seemed more fluid. I think it might be the backgrounds in Zero Mission that are throwing me off. I know the original just had the standard NES black background, but the ones made for Zero Mission seem so much like generic stock art, like the backgrounds for custom stages in Super Smash Brothers Brawl. Although the Kirby dots are neat. Never noticed those before.
I will give Zero Mission props for doing something that Fusion didn't get. Zero Mission's scarier. Fusion was pretty predictable. Go to X (variable, not the parasite) location, get X, fight X (variable and parasite). So you're usually prepared for the boss since you get a red X parasite from the boss door to heal you. The bosses have been just popping out of nowhere in Zero Mission. Pretty shocking for someone playing the game on sleeping pills.