Metal Slug Zero Online

Metal Slug Zero Online is an upcoming online multiplayer game for the Metal Slug series. The developer is the South Korean based company, Dragonfly, who is best known for being one of the co-developers for Quake Wars Online. They first received permission for the project on July 19, 2007. They also gained the licenses for the online versions of The King of Fighters and Samurai Shodown.

The game is currently going through in it's beta stages and is scheduled for to be released in 2009. So far, this title is planned exclusively for the Asian and Oceanian regions.

Story
Several years after the events of Metal Slug 5, General Morden has given up on conquering the world and is instead hellbent on his new plan: to annihilate the entire human race by destroying the ecosystem. The Martians, Venusians (the new race of aliens that appeared in Metal Slug 6) and Ptolemaic threats have not been confirmed to be neutralized completely. As such, nations around the world become highly dependent on the Regular Army forces. With the growing necessity of the Regular Army, new addition of troops to the Peregrine Falcons and Sparrows, both being small and little-known special forces branches that are often given near-impossible missions, are expected.

Gameplay
The game will be in 3D but the gameplay will still be in side-scrolling form. Marco, Tarma, Eri, and Fio are playable though new characters are also in the works. Four people are able to play simultaneously in a game. New enemies are to be included as well.

All items will be able to be collected as cards and stored in a cardbook called "Metal Book", which will be ranked depending on how many cards that the player has collected from levels F from the lowest to A at the highest. When 100% is reached at level A, the player will be able to proceed to the next episode and access newer systems and contents, while the rank is reset to F. This process will be repeated for player advancements.