Mega Man Zero, known in Japan as Rockman Zero (ロックマン ゼロ, Rokkuman Zero), is a spin-off of the popular series Mega Man X (Which itself is a spin-off of the classic Mega Man series), and follows closely to the 2D side-scrolling, platforming gameplay established in its forerunners. You play as Zero, a Maverick Hunter who appeared in previous Mega Man X games as a playable character. Unlike X, who can only shoot his enemies, Mega Man Zero introduces close-combat gameplay from the start with the addition of the Z-Sabre, Zero's blade and weapon of choice. It also introduces several new weapons not seen in previous Mega Man games, such as the Triple Rod and Shield Boomerang. Apart from the inclusion of classic 2D gameplay, the game differs wildly from its predecessors. It introduces several new gameplay features, notably the Mission System, Cyber Elves, weapon upgrades, and elemental powers.
In previous Mega Man games, you would select which level to play via a menu listing all the Robot Masters that you had left to fight. In Mega Man Zero, You start from an overworld, the Resistance base, and can take on missions from there. At some point in a mission (not always at the end, unlike previous Mega Man games) you would fight a boss character, usually some form of maverick robot. Completion of that mission usually results in a reward of some kind, ranging from Cyber Elves to new weapons. If you choose to leave a mission once you've started it, or lose all you lives within a mission, you fail that mission and cannot retry it. However, again unlike previous games you can still continue with the story without failing non-critical missions. Failing a critical mission will result in a game over and you will be returned to the last game save you made prior to your death.
Cyber Elves are arguably the largest gameplay change from other games in the Mega Man series. They could be found all over the place. Some require you to beat a type of enemy multiple times, some are in hidden areas. Cyber Elves are powerful computer AI programs that have a form in the physical realm. Their use can be related to that of power-ups. Each Cyber Elf gives Zero a different ability or causes a different effect. These range giving Zero a temporary health boost, to reducing the boss character's health by half. The majority of the elves are ready for use once you collect and equip them. However, some (especially the rarer ones) require you to feed them energy crystals to grow and then be used. Note that every time you use a cyber elf, your score would be deducted depending on how much elves you use and their quality.
The game assigns an overall rank to the player, ranging from F to S. This rank is determined by the average amount of points you have earned from each completed mission.
- S: 100 - 96
- A: 95 - 86
- B: 85 - 76
- C: 75 - 66
- D: 65 - 56
- E: 55 - 46
- F: 45 - 0
The points you earn are displayed at the mission results screen at the end of each level. Your mission point total is based on how well you meet the following criteria:
- Mission Success (20) - Some stages contain a specific task or requirement that must be met. If it doesn't, then the full amount is automatically awarded upon mission clear.
- Clear Time (20) - Each stage has a unique time limit in which it must be cleared for full credit.
- Enemy (15) - Each stage has a set enemy kill count you must reach for full credit.
- Damage (15) - The more damage you take, the lower your score.
- Retry (15) - Based on how many lives were lost. Not dying yields full credit.
- Elf (15) - Based on how many Cyber Elves were used. Using none awards full credit. Using any Elves that give permanent bonuses, such as Sub Tanks or vitality boosts, will subtract from this score for the remainder of the game.