Zero Mission is a remake of Samus' first adventure in the original Metroid for the NES. Luckily Nintendo didn't just put on some make up for her, they gave her a complete make over. While this game remains the same at heart, it does have some major differences.
In it's bare bones state, the game still has the same layout as the original but many key differences have been made. First and foremost, a save system. No more writing down passwords, multiple save rooms have been added around every area. A lot of the areas have had some minor changes and additions as well. The developers have also added many new abilities and weapons for our heroine. She moves much faster and the overall pace of the game feels faster as well. The best part is the newly added bonus area exclusive to Zero Mission. It's sort of an epilogue of what happens to Samus after she defeats Mother Brain. For half of this mission, Samus is stripped of her suit and weapons and must explore a Space Pirate base with only a stun gun. This extra mission combines stealth and is very tense. It's a very fine addition to what is already a great game. But sadly, even with the extra mission the game is rather short. It'll average about 5 hours to finish and maybe 8 to fully complete. Luckily, the full version of the original Metroid (with the password system) has been included but that's been included with Fusion as well.
The obviously looks better, that's easy to realize from seeing any screenshots of the game. The game looks very much like Fusion. Everything looks more organic and detailed and the game runs fluidly. The art direction is definitely nice. There are some nice still images used a story bits in the game which are also nice.
The game sounds great but like almost all GBA games, headphones are a must for the best audio experience. The sound effects are chrisp and clean and always on target. The musical score is as exceptional as ever. The game selection track (which was the title track for the original game) alone is very mysterious.
The main point of remaking this game is to familiarize the new Metroid fans to Samus' beginnings. And this game does it well. The story will make many things clearer for all, even if you played the original to death.
Final words: Whether you're a novice or a veteran, you definitely need to play Zero Mission.